Surgical manipulator

ABSTRACT

The present invention provides a surgical manipulator including a manipulator arm, an end-effector held by the robotic arm, surgical tools held by the end-effector and manipulator joints, particularly right-angle drive devices for transmitting rotational motion in one axis to a perpendicular axis.

CROSS REFERENCE TO RELATED U.S. PATENT APPLICATIONS

This patent application relates to U.S. utility patent application Ser.No. 60/813,353 filed on Jun. 14, 2006 entitled SURGICAL MANIPULATOR,filed in English, which is incorporated herein in its entirety byreference.

FIELD OF THE INVENTION

The present invention relates to a surgical manipulator including amanipulator arm, an end-effector held by the manipulator arm, surgicaltools held by the end-effector and manipulator joints, particularlyright-angle drive devices for transmitting rotational motion in one axisto a perpendicular axis.

BACKGROUND OF THE INVENTION

The goal of surgical manipulator systems is to apply robotic and sensortechnologies to improve the quality of patient surgical outcomes in acost-effective manner. Surgical robotics can attain this goal throughrepeatable increased spatial resolution and better geometric accuracy ofsurgical tools positioning by the surgeon, faster operating speed, goodergonomics that can reduce the surgeon's fatigue, and the ability toprovide a platform for surgeon training and education.

A number of commercial surgical robotic systems are currently in useincluding the NeuroArm Magnetic Resonance Imager (MRI) compatibleneurosurgical robot by the University of Calgary, the da Vinci and Zeussurgical robots by Intuitive Surgical, the RAMS system by Microdexterityand the Jet Propulsion Laboratory, the Haptic Guidance System by MAKO,the SpineAssist by Mazor Surgical Technologies, as well as ROBODOC ofIntegrated Surgical Systems.

The University of Calgary neuroArm system is designed to performneurosurgery in an MRI environment. It has dual arms, each with 6Degrees of Freedom in a master-slave configuration. The robot is MRcompatible so no magnetic material is used for any part of the robotarm. It also has haptic feedback capability for sensing tool tip forces.Surgical tool changes are performed manually, see U.S. Pat. No.7,155,316.

The Intuitive Surgical da Vinci system is designed for laparoscopicsurgery. It can have up to 5 arms controlled by the surgeon in aMaster-slave control configuration. The system is large and heavy with aweight greater than 1000 lbs. There is no haptic feedback and toolchanges are performed manually. The Zeus is a discontinued product thatwas also designed for laparoscopic surgery. Smaller and lighter than theda Vinci, the Zeus also had up to 5 arms in a Master-slave controlarchitecture with no haptic capability and manual tool changes. (diVinci: patents see attached list; Zeus: U.S. Pat. No. 5,515,478, U.S.Pat. No. 5,553,198, U.S. Pat. No. 5,645,520, U.S. Pat. No. 6,646,541,U.S. Pat. No. 6,714,841 etc)

Originally developed by JPL, the Robot-Assisted Micro-Surgery (RAMS)system is being commercialized by MicroDexterity. This teleroboticplatform is designed for microsurgery on brain, eye, ear, nose, throat,face, and hand. Clinical tests had been performed on neurosurgery andhand surgery. The dual-arm system is very compact; the manipulator isapproximately 25 mm in diameter and 250 mm long. The robot has aMaster-slave architecture and exhibits high spatial resolution of 10microns. The system has indirect pressure and texture sensing of thetool forces using joint encoder information. The surgical tools arechanged manually, see U.S. Pat. No. 6,702,805.

The MAKO Haptic Guidance System targets knee replacement surgeries bymeans of a robotic system that assists the surgeon in arthroplastythrough keyhole incisions. The FDA-approved system allows surgeon topre-operatively optimize the size and alignment of knee, and executesurgeon-guided knee sculpturing and implant placing with CTimage-guidance, see US patent Publications 20060142657, 07206627,07139418)

Mazor Surgical Technologies developed the SpineAssist as a minimallyinvasive guidance systems for pedicle screw insertion as well as otherspine related procedures. In the size of a soda can, the SpineAssist isa parallel-platform robot mounted onto the patient's spine or spinousprocess. Pre-operative planning with CT images is followed by automaticfluoroscope or CT image registration to the robot, after which thepositioning device automatically directs its arm in the trajectoryplanned by the surgeon, with accuracy less than 1.5 mm.

In 1992, Integrated Surgical Systems introduced the ROBODOC, a largeorthopedic surgical system intended for use in patients requiringprimary cementless total hip replacement surgery. It has a single 6 DOFarm that operates automatically using a pre-operatively defined program.It has no haptic feedback capability and tool changes are performedmanually, see US Patent Publications 20040142803, 05766126, 06239874,06349245.

There are a number of aspects of the existing state of surgical robotictechnology that require major improvements. The development of robotarms that are dexterous, precise and have large workspaces both in howthey attain the work site location and when they are inside bodycavities and organs. The overall size, weight and volume of most currentsystems are a major issue in that they have a major detrimental impacton operating room facility space and the support staff who set-up theequipment. Smaller, lighter weight stowable systems are needed. Forexample, the da Vinci surgical manipulator weighs 1200 lbs (exclusive ofthe operator interface) and stands approximately 8 ft. The Zeus arms areapproximately 2 ft long and weigh 40 lbs. Total weight of the robot is120 lbs. (exclusive of the user interface).

The majority of current systems do not provide Haptic feedback. Hapticfeedback restores the lost sense of touch for the surgeon and mayimprove the surgeon's performance in terms of speed and reducing risk ofcollateral tissue damage.

Manual surgical tool exchange increases the surgical operating time;increasing the time the patient is required to remain under anaesthesiaand increasing facility costs. The ability to automatically exchangesurgical tools would therefore reduce patient risks and lower operatingcosts.

The high mechanical power density and small diameter of conventional dcmotor servomotors are desirable traits to reduce the physical dimensionsof robotic manipulators. However, the drawback of conventionalservomotors presently in use in many surgical robots is their long axiallength, so a right-angle transmission means is needed if excessivelateral extension of the manipulator arm joints is to be avoided.

Of all the available right-angle transmission components at present,bevel gear pairs deliver high torque and backdrivability, but backlashis typically high and they seldom come in small packages. Thetraditional standard bevel gear box has large backlash in transmissionwhich is highly undesirable in applications where high precision isrequired in both directions of motion.

There are several manufacturers offering worm gears in a small package,and integrating with spring-loaded features the gearbox can be backlashfree and achieve precise motion, but the lowered efficiency and the oddstandard gear ratio increment suggest that more powerful (thus larger insize) motors will be needed. Worm gear boxes can have low-backlashconfigurations but its indirect proportional relationship between theefficiency versus the gear ratio leads to a bulkier and heavier overallunit, while also the lack of back-drivability is also undesirable in theevent of crash recovery or calibration common to robotics applications.

Harmonic drives, on the other hand, features zero-backlash, highlyrepeatable precision, back-drivability, high efficiency, compact sizeand lightweight. Unfortunately, the mechanism does not allow for aright-angle drive version. No commercially available right-angletransmission in the market currently has both zero-backlash and highefficiency capabilities in a compact in-line package.

Therefore, it would be very advantageous to provide a surgical roboticsystem employing right angle drives which avoids the above mentioneddrawbacks.

SUMMARY OF THE INVENTION

The present invention provides embodiments of a surgical manipulatorincluding a manipulator arm, an end-effector held by the manipulatorarm, surgical tools held by the end-effector and manipulator joints,particularly right-angle drive devices for transmitting rotationalmotion in one axis to a perpendicular axis.

In one aspect of the invention there is provided surgical manipulator,comprising:

a) a base and a first right-angle drive mechanism mounted on said base,a shoulder-roll drive mechanism located in said base for rotating saidfirst right-angle drive mechanism about a shoulder-roll axis, said firstright-angle drive mechanism including a first input pulley and a firstoutput pulley mounted substantially perpendicular to said input pulley;

said first right-angle drive mechanism including a bi-directionalcoupling mechanism for coupling said first input pulley and said firstoutput pulley, a first drive mechanism for rotating said first inputpulley about a first input axis wherein rotation of said first inputpulley is translated into rotation of said first output pulley by saidbi-directional coupling mechanism about a shoulder-pitch axis which issubstantially perpendicular to said first input axis;

b) a lower robotic arm being mounted at one end thereof to said firstoutput pulley so that when said first output pulley is rotated, saidlower arm rotates about said shoulder-pitch axis;

c) a second right-angle drive mechanism mounted in said lower roboticarm, said second right-angle drive mechanism including a second inputpulley and a second output pulley mounted substantially perpendicular tosaid second input pulley,

said second right-angle drive mechanism including said first drivemechanism and said bi-directional coupling mechanism for coupling saidsecond input pulley and said second output pulley, wherein rotation ofsaid second input pulley about a second input axis is translated intorotation of said second output pulley by said bi-directional couplingmechanism about an elbow-pitch axis substantially perpendicular to saidsecond input axis;

c) a robotic fore arm mounted on said second output pulley of saidsecond right-angle drive mechanism so that when said second outputpulley is rotated, said robotic fore arm rotates about said elbow-pitchaxis;

d) a third right-angle drive mechanism mounted in said robotic fore arm,said third right-angle drive mechanism including a third input pulleyand a third output pulley mounted substantially perpendicular to saidsecond input pulley,

said third right-angle drive mechanism including said first drivemechanism and said bi-directional coupling mechanism for coupling saidthird input pulley and said third output pulley, wherein rotation ofsaid third input pulley about a third input axis is translated intorotation of said third output pulley by said bi-directional couplingmechanism about a wrist-pitch axis substantially perpendicular to saidthird input axis;

e) a robotic wrist mounted on said third output pulley of said thirdright-angle drive mechanism so that when said third output pulley isrotated, said robotic wrist rotates about said wrist-pitch axis;

said robotic wrist including an actuation mechanism coupled to a wristoutput shaft for rotating said robotic wrist output shaft about awrist-roll axis; and

f) an end-effector mounted to said wrist output shaft, said end-effectorincluding gripping means for releasibly gripping a surgical tool whereinwhen said actuation mechanism is engaged said end-effector is rotatedabout said wrist-roll axis.

The present invention also provides a surgical manipulator system,comprising:

a) at least first and second surgical manipulators which are configuredto be structural mirror images of each other, said first surgicalmanipulator being configured for left handed operation and said at leasta second surgical manipulator being configured for right handedoperation to allow the surgical tools attached to respectiveend-effectors to be brought into closest proximity with each other in asurgical site on a patient. The surgical manipulator system includesleft and right hand controllers with the right hand controller beingassociated with the first surgical manipulator and the left handcontroller being associated with the second surgical manipulator, saidat least first and second hand controllers being configured to beoperated by a surgeon. The system includes a communication systemcoupling said left and right hand controllers to said at least first andsecond surgical manipulators for translating movement of said left andright hand controllers to scaled movement of said at least first andsecond surgical manipulators.

The present invention also provides a surgical end-effector, comprising:

a main body portion including a frame having an interface configured tobe attached to a robotic arm, a tool-yaw motor mounted on said frame, atool-actuation motor mounted on said frame;

a tool holder mounted on said frame and being detachable therefrom, saidtool holder being configured to hold a surgical tool;

a tool-actuation mechanism mounted on said frame and being detachabletherefrom, said tool-actuation mechanism being configured to engage apiston on said surgical tool, said tool-actuation mechanism beingcoupled to said tool-actuation motor; and

and a tool-yaw drive mechanism mounted on said frame and beingdetachable therefrom, said tool-yaw drive mechanism being coupled tosaid tool-yaw motor, wherein upon activation of said tool-yaw drivemechanism said surgical tool rotates about said tool-yaw axis andwherein upon activation of said tool-actuation mechanism said piston islinearly retracted or linearly extended with respect to saidend-effector thereby activating a tool portion of said surgical tool.

The present invention also provides embodiments of a compact right-angletransmission drive with substantially zero-backlash that uses cablesrather than traditional gears to transmit rotational motion in one axisto a perpendicular axis. In this aspect of the invention there isprovided a drive device for transmitting rotational motion about oneaxis to rotational motion about another axis, comprising:

a) a housing and a harmonic drive mounted on said housing beingconnected to an input pulley for rotation about a first rotational axis;

b) an output drive shaft having a second axis of rotation, said outputshaft being connected to an output pulley, said output pulley beingmounted in said housing for rotation about said second rotational axis,said input and output pulleys being mounted in said housing andpositioned with respect to each other such that a pre-selected angle isestablished between said first and second axes of rotation;

c) bi-directional coupling mechanism for coupling said first inputpulley and said first output pulley, comprising

-   -   a cable drive mounted in said housing, said cable drive        including,    -   at least one flexible cable, said input and output pulleys each        including at least one cable guide for receiving therein said at        least one flexible cable,    -   idler means for guiding said at least one flexible cable between        said input and output pulleys,        wherein when the input pulley rotates in one direction about        said first axis of rotation, said at least one flexible cable        pulls the output pulley and output shaft to rotate in one        direction about said second rotational axis, and when the input        pulley rotates in the other direction about said first axis of        rotation, said at least one flexible cable pulls the output        pulley and output shaft to rotate in an opposite direction about        said second rotational axis.

A further understanding of the functional and advantageous aspects ofthe invention can be realized by reference to the following detaileddescription and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be more fully understood from thefollowing detailed description thereof taken in connection with theaccompanying drawings, which form a part of this application, and inwhich:

FIG. 1 is an isometric view of an assembled right-angle drive systemconstructed in accordance with the present invention;

FIG. 2 is an exploded, disassembled view of the right-angle drive systemof FIG. 1;

FIG. 3 a is an isometric view of the output shaft forming part of theright angle drive;

FIG. 3 b is a side view of the output shaft of FIG. 3 a;

FIG. 3 c is a view of the output shaft along the arrow 3 c in FIG. 3 b;

FIG. 4 a is an isometric view of a mid-housing forming part of the rightangle drive;

FIG. 4 b is a front view of the mid housing of FIG. 4 a;

FIG. 4 c is a cross sectional view along the line A-A of FIG. 4 b;

FIG. 4 d is equivalent to the view direction of FIG. 4 c but showing allsurface features of the mid housing;

FIG. 4 e is a bottom view of FIG. 4 b along the arrow 4 e;

FIG. 4 f shows a bearing mounting on the output shaft of FIG. 3 amounted in the mid-housing of FIG. 4 a;

FIG. 5 a is an isometric view of an output pulley forming part of theright angle drive;

FIG. 5 b is a front view of the output pulley of FIG. 5 a;

FIG. 5 c is a bottom view of FIG. 5 b;

FIG. 5 d is a cross sectional view along the line A-A of FIG. 5 b;

FIG. 5 e is a detail view of FIG. 5 d showing the details of thetensioning mechanism;

FIG. 5 f is a top view of FIG. 5 b;

FIG. 6 a is an isometric view of an input pulley forming part of theright angle drive;

FIG. 6 b is a front view of the input pulley of FIG. 6 a;

FIG. 6 c is a top of FIG. 6 a;

FIG. 6 d is a cross sectional view along the line C-C of FIG. 6 b;

FIG. 6 e is a cross sectional view along the line B-B of FIG. 6 b;

FIG. 6 f is a view of the cable termination subassembly with a loopsleeve crimped fitting;

FIG. 6 g is a cross-section view of the input and output pulleys ofFIGS. 5 a and 6 a illustrating the grooved circumference on both theinput and output pulley for the cable wrapping;

FIG. 7 a shows an isometric view of an idler shaft forming part of theright angle drive;

FIG. 7 b shows a front view of the idler shaft of FIG. 7 a;

FIG. 8 shows the relative positions of the input and output pulleysperpendicular to each other and the driving cables and idlers forconverting rotational motion of the input pulley into rotational motionof the output shaft oriented perpendicular to the input axis;

FIG. 9 a shows an isometric view of a tensioning screw forming part ofthe right angle drive;

FIG. 9 b shows a cross-sectional view along line 9 b of FIG. 9 d;

FIG. 9 c shows the side view of the tensioning screw of FIG. 9 a;

FIG. 9 d shows the front view of the tensioning screw of FIG. 9 a;

FIG. 10 a shows the front view of the assembled right-angle drive;

FIG. 10 b shows the cross-sectional view of FIG. 10 a along the line A-Aof FIG. 10 a;

FIG. 10 c shows the detailed view of section C in FIG. 10 b for theidler subassembly;

FIG. 11 a shows the assembled side view of the right-angle drive withthe output pulley front face;

FIG. 11 b shows a cross-sectional view of FIG. 11 a along line B-B ofFIG. 11 a for the output elements;

FIG. 11 c shows a cross-sectional view of FIG. 11 a along line C-C ofFIG. 11 a for the input elements and the top idler subassembly;

FIG. 12 shows a side cross-sectional view of the input elements;

FIG. 13 shows the opposite assembled side view to FIG. 11 a;

FIG. 14 shows a perspective view from a top-front angle of the assembledright-angle drive of FIGS. 1 and 2 without the cover and idler caps;

FIG. 15 shows a perspective view from a top-rear angle of the assembledright-angle drive without the cover and idler caps;

FIG. 16 a is an isometric view of a surgical robot forming part of thepresent invention;

FIG. 16 b is a side view looking along arrow b of FIG. 16 a;

FIG. 16 c is a front view looking along arrow c of FIG. 16 a;

FIG. 16 d is a top view looking along arrow d of FIG. 16 a;

FIG. 16 e is another an isometric view of the surgical manipulatorsimilar to FIG. 16 a but looking from the opposite direction;

FIGS. 17 a to 17 e show details of the manipulator base forming ashoulder-roll joint assembly;

FIG. 17 a is an isometric view of the manipulator base without thecover;

FIG. 17 b is a top view of FIG. 17 a along the arrow b;

FIG. 17 c is a front cross-section view of FIG. 17 b along the line c-cshowing the actuation components of the shoulder-roll joint;

FIG. 17 d is a side cross-section view of FIG. 17 b along d-d showingthe actuation components of the shoulder-roll joint;

FIG. 17 e is a front cross-section view of FIG. 17 b along e-e showingthe actuation components of the shoulder-roll joint and showing thecover 402;

FIGS. 18 a to 18 e show details of the manipulator shoulder with theright angle drive mounted on top of the shoulder-roll driven shaftforming a shoulder-pitch joint assembly;

FIG. 18 a is an isometric view of the manipulator shoulder;

FIG. 18 b is a front view of FIG. 18 a along the arrow b;

FIG. 18 c is a top view of FIG. 18 a along the arrow c;

FIG. 18 d is a cross-section view of FIG. 18 c along the line d-d;

FIG. 18 e is a side view of FIG. 18 a along the arrow e

FIGS. 19 a to 19 e show details of the manipulator lower arm and theright angle drive mounted at the front of the manipulator lower armforming an elbow-pitch joint assembly;

FIG. 19 a is an isometric view of the lower manipulator arm;

FIG. 19 b is a front view of FIG. 19 a along the arrow b;

FIG. 19 c is a side view of FIG. 19 a along the arrow c;

FIG. 19 d is a top view of FIG. 19 a along the arrow d;

FIG. 19 e is a cross-section view of FIG. 19 c along the line e-e;

FIGS. 20 a to 20 f show details of the manipulator upper arm and theright angle drive mounted at the front of the manipulator upper armforming a wrist-pitch joint assembly;

FIG. 20 a is an isometric view the manipulator fore arm;

FIG. 20 b is a side view of FIG. 20 a along the arrow b;

FIG. 20 c is a bottom cross-section view of FIG. 20 b along line c-c;

FIG. 20 d is a top view of FIG. 20 a along the arrow d;

FIG. 20 e is a back cross-section view of FIG. 20 b along e-e;

FIGS. 21 a to 21 e show details of the manipulator wrist forming awrist-roll joint assembly;

FIG. 21 a is an isometric view of the wrist;

FIG. 21 b is a top view of FIG. 21 a along the arrow b;

FIG. 21 c is a front cross-section view of FIG. 21 b along line c-c;

FIG. 21 d is a front view of FIG. 21 a along the arrow d;

FIG. 21 e is a side cross-section view of FIG. 21 b along line e-e;

FIGS. 22 a to 25 b show details of the surgical forcep tools;

FIG. 22 a is an isometric view of a first embodiment of a surgical tool;

FIG. 22 b is a side view of the surgical tool of FIG. 22 a;

FIG. 22 c is a bottom cross-sectional view along the line c-c of FIG. 22b with the surgical tool in the open position;

FIG. 22 d is a bottom cross-sectional view along the line c-c of FIG. 22b with the surgical tool in the closed position;

FIG. 22 e is a back cross-sectional view along the line e-e of FIG. 22a;

FIG. 23 a is an isometric view of an alternative embodiment of asurgical tool in the opened position;

FIG. 23 b is an elevational view of the surgical tool of FIG. 23 a;

FIG. 24 a is an isometric view of an alternative embodiment of asurgical tool in the closed position;

FIG. 24 b is an elevational view of the surgical tool of FIG. 24 a;

FIG. 25 a is an isometric view of another alternative embodiment of asurgical tool; and

FIG. 25 b is an elevational view of the surgical tool of FIG. 25 a.

FIG. 26 a is an isometric view of an assembled end-effector holding asurgical tool forming part of the present invention;

FIG. 26 b is a disassembled view of the end-effector and surgical tool;

FIG. 26 c is a front view of FIG. 26 a;

FIG. 26 d is a side view of FIG. 26 a showing the force-path of thepinch force as a result of tool-actuation;

FIG. 26 e is a cross-sectional view of the assembled end-effectorholding a surgical tool along the line c-c of FIG. 26 c showing theload-path of the tip force monitored by the force-moment sensor;

FIG. 27 a is a top view of the tool-yaw subassembly;

FIG. 27 b is a bottom view of the tool-yaw subassembly;

FIG. 27 c is a top view of the assembled end-effector;

FIG. 27 d is a bottom view of the assembled end-effector;

FIG. 27 e is a top view of the main end-effector body;

FIG. 27 f is a cross-sectional view of FIG. 27 e along the line f-fshowing the load-path of the tip force monitored by the force-momentsensor;

FIG. 28 a is a top view of the tool actuator;

FIG. 28 b is a cross-sectional view of the tool actuator along the lineb-b of FIG. 28 a;

FIG. 29 a is a front view of the tool holder;

FIG. 29 b is a cross-sectional view of the tool holder along line b-b inFIG. 29 a;

FIG. 29 c is an isometric view of the tool holder;

FIG. 29 d is a top view of the tool holder showing the tool ejectionwings in the engaged configuration;

FIG. 29 e is a top view of the tool holder showing the tool ejectionwings in the ejected configuration;

FIG. 29 f is an isometric view of the end-effector releasing the tool atthe tool tray;

FIG. 30 is a schematic diagram showing the operation concept of adual-manipulator telerobotic system controlled by a surgeon in a typicaloperating theatre.

DETAILED DESCRIPTION OF THE INVENTION

Generally speaking, the systems described herein are directed to asurgical manipulator apparatus. As required, embodiments of the presentinvention are disclosed herein. However, the disclosed embodiments aremerely exemplary, and it should be understood that the invention may beembodied in many various and alternative forms. The Figures are not toscale and some features may be exaggerated or minimized to show detailsof particular elements while related elements may have been eliminatedto prevent obscuring novel aspects. Therefore, specific structural andfunctional details disclosed herein are not to be interpreted aslimiting but merely as a basis for the claims and as a representativebasis for teaching one skilled in the art to variously employ thepresent invention. For purposes of teaching and not limitation, theillustrated embodiments are directed to a surgical manipulatorapparatus.

The surgical manipulator apparatus comprises a multi-jointed roboticarm, with the different booms connected to right angle drive units, andsurgical end-effectors connected to a robotic wrist unit. Each of thesecomponents will now be described in detail.

1) Right Angle Drive Unit

Referring first to FIG. 1, an isometric view of an assembled right-angledrive system is shown generally at 10 which includes a housing comprisedof a chassis 14 and a cover 16. Referring particularly to FIG. 2, theright angle drive system 10 includes an output pulley 20, an outputshaft 26 on top of which the output pulley 20 is mounted to, a midhousing 22, a pair of idler units 78, 86, 84, 80 a/b, 82 a/b, an opticalencoder 46, and an input pulley 54 mounted on a drive mechanism whichpreferably comprises a harmonic-drive 56.

Referring to FIG. 2 and FIGS. 3 a and 3 b, the optical encoder 46 ismounted on shaft section 38 of output shaft 26 for measuring rotationaldisplacement of the output shaft 26. The typical optical encoder 46measuring system includes a light source, a code disk rotating about aninternal or external precision ball bearing and an optical light sensor.The code disk has a series of opaque and transparent markings whichspatially encode the angular position of the shaft section 38 that maybe configured to provide the absolute or relative angular position ofthe shaft. A light source shines through the code disk and onto theoptical light sensor. Every angular position has coded dark spots andlight spots on the code disk which interrupt the light beam on theoptical light sensor, from which electronic signals are generated. Theelectronic signals are amplified and converted into angularposition/speed data which can be used by a control system.

For an incremental encoder embodiment, all the markings on the code discare identical, and electronic signals are generated in the form ofpulses which are counted by the controller to determine the relativepositioning or differentiated against time to obtain speed. For anembodiment which uses an absolute encoder, each marking on the code discis distinctively formed by a series of lines, and the resultingelectronic signal from the light detection of the optical sensor will bea unique binary code which makes absolute position sensing possible.

The harmonic-drive 56 is mounted to the chassis 14, and on the outputflange 98 of the harmonic-drive 56 an input pulley 54 is mounted and hasan axis of rotation perpendicular to that of the output pulley 20. Theharmonic-drive 56 is used to introduce high reduction ratio to theoverall right-angle drive 10. The cable-pulley system thus is onlyresponsible for the angled transmission of motion from the input to theoutput side and thus forms a bi-directional coupling mechanism sincerotation of the input shaft about its axis in one direction causesrotation of the output shaft about its axis in one direction, androtation of the input shaft by the drive mechanism in the otherdirection causes rotation of the output shaft about its axis in theother direction.

FIGS. 6 a to 6 e, and FIG. 12 show details of the input pulley 54. Inputpulley 54 includes two sections, an auxiliary section 130 and a mainsection 132 with the auxiliary section 130 having a larger diameter thanthe main section 132 to accommodate for the vertical locations of themain idlers 80 a, 80 b and auxiliary idlers 82 a, 82 b (FIG. 1).Sections 130 and 132 have circular grooved circumferences 134 and 136with spiral continuous grooves 160 (FIG. 6 g) on the surfaces to providefriction between the cable and the input pulley 54 such that the drivingtorque for the pulley by the cable is distributed evenly about thepulley and not completely relying on the termination at the loopedcrimped fittings 101 (FIG. 6 f) located inside the pockets 138 and 140.The cables are terminated at the input pulley 54 by threading into thecorresponding lateral access holes 141 a, 141 b, 141 c, 141 d andthrough the pockets 140 a, 138 a, 140 b, 138 b respectively.

The loop crimp fittings 101 provided by the cable manufacturer arecrimped onto the tip of the cables with each forming a loop at the otherend of the fitting as shown in FIG. 6 f. Each fitting together with theloop hides inside the pockets 138 a, 138 b, 140 a, 140 b, in which wheneach cable is under tension its fitting will ride up against theinternal wall of the pocket and maintain the cable tension.

Referring to FIGS. 6 a, 6 g, 8 and 11 c, cable 92 b (FIG. 8) is wrappedaround the main section 132 (FIG. 6 a) of the input pulley 54 along thecircular groove section 160 (FIG. 6 g) which is machined on thecircumferential surface 136 in a spiral helical path along the center ofrotation of the pulley. The direction of which cable 92 b winds aroundthe surface 136 (FIG. 6 a) is counter-clockwise starting from thelateral access hole above the loop sleeve termination pocket 138 a andlooking into the input pulley 54 in the view direction of FIG. 6 b. Whenthe cable 92 b is inside the groove 160, the surface friction in betweenthe two assists in the input pulley 54 driving the cable 92 b withtension which in turn drives the output pulley 20, thus relieving someof the stress concentrated at the loop sleeve fitting 101 (FIG. 11 c)where the cable is terminated. The adjacent groove section 161 (FIG. 6g), which is wound around by cable 92 a (FIG. 8) clockwise, may or maynot be continuous with section 160 depends on the axial length of themain cable section 132. The identical relationship applies to theauxiliary cable section 130 as groove section 162 (FIG. 6 g) is forcable 90 b (FIG. 8) winding counter-clockwise and groove section 163(FIG. 6 g) is for cable 90 a (FIG. 8) winding clockwise.

Referring to FIGS. 3 a, 3 b and 3 c, the output shaft 26 includes acylindrical housing 36 and a shaft 38 extending from the rear face 40 ofthe output shaft 26 and the rear face 40 includes a circumferentialshoulder 42 of a larger diameter than the diameter of cylindricalhousing 36. There is a centered hole 28 located on a front face 30 toreceive therein a centering dowel 32 which forms the rotating outputseen in FIG. 1 protruding from the center of output pulley 20. Referringto FIG. 4 f, a radial ball-bearing 59 is mounted on shaft 38 betweenwhich the shoulder 42 of the output shaft 40 the encoder 46 issandwiched.

Referring to FIGS. 4 a to 4 f, the mid-housing 22 includes a pair ofcircular bores 70 and 72 which are match-machined to be perfectlyconcentric to each other for the angular-contact ball-bearings 24 shownin FIG. 1. The diameter 68 which is smaller than that of 70 and 72 issized according to the recommended outer ring shoulder landing diameterspecified by the bearing manufacturer. Details of the mounting andpreloading of the angular-contact ball-bearing pair 24 insidemid-housing 22 will be described later. Mid-housing 22 includes an idlersupport section 74 (FIG. 4 a) having two holes 76, one on the topsurface and the other on the bottom surface for receiving idler shafts78 which are part of the main idler mechanisms, shown in FIG. 2.

Referring to FIGS. 4 f and 11 b, the two angular-contact ball-bearings24 are mounted inside the bearing seats 70, 72 in a back-to-backconfiguration (best seen in FIG. 4 f). The bearings 24 are seated withtheir respective outer ring 139 inside the concentric bore 72 and 70.The locknut 60 is turned on the output shaft 26 via a threaded section43 (FIG. 3 a), which provides loading from the locknut 60 via the outputshaft 26 to the inner ring 142 of the bearing adjacent to the locknut 60(see FIG. 4 f). The loading will be transmitted from the inner ring 142through the balls 143 and to the outer ring 139 of that bearing,following the load path outlined along 140 shown in dotted lines, andend up back at the output shaft 26 again at the flange 40 (FIG. 3 b).The preload is completed when the inner gap inside the raceway of thebearings 24 between the balls 143 and the inner ring 142 and outer ring139 is eliminated by the motion of the locknut 60 towards the bearingpairs along the output shaft 26 as a result of the turning of thelocknut 60. This procedure is carried out by means of the use of atorque wrench to tighten the locknut 60 on output shaft 26, using atorque level recommended by the bearing manufacturer for installation.

FIGS. 5 a to 5 f inclusive show details of the output pulley 20. Outputpulley 20 includes two sections 110 and 112 with the auxiliary section110 having a larger diameter than the main section 112 to accommodatefor the vertical locations of the main 80 a, 80 b and auxiliary idlers82 a, 82 b. Sections 110 and 112 have circumferences 114 and 116respectively with continuous spiral grooves 160 (of FIG. 6 g) on thesurfaces to provide friction between the cable and the output pulley 20in order to distribute the driving torque evenly about the pulley 20 andrelieve stress on the termination at the tensioning screws 94 a, 94 band 96 a, 96 b thereby reducing the possibility of detachment. FIG. 11 ashows the front view of the drive unit showing the positioning of thetensioning screws in the holes 144 a, 144 b, 146 a and 146 b.

Referring to FIGS. 5 a, 6 g and 8, cable 92 b (FIG. 8) is wrapped aroundthe main section 112 (FIGS. 5 a and 8) of the output pulley 20 along thecircular groove 160 (FIG. 6 g) which is machined on the circumferentialsurface 116 (FIG. 5 a) in a spiral helical path along the center ofrotation of the pulley 20. The direction of which cable 92 b windsaround the surface 116 is counter-clockwise starting from the lateralaccess hole above the tensioning screw hole 146 a and looking into theoutput pulley 20 at the output load interface surface. When the cable 92b is inside the groove 160, the surface friction in between the twoassists in driving the output pulley 20 to rotate counter-clockwise whenthe cable 92 b is under tension, thus relieving some of the stressconcentrated at the tensioning screw 96 b inside the tensioning screwhole 146 a where the cable is terminated. The adjacent groove section161 (FIG. 6 g), which is wound around by cable 92 a (FIG. 8) clockwise,may or may not be continuous with groove 160 depending on the axiallength of the main section 112. The identical relationship applies tothe auxiliary section 110 as groove section 162 (FIG. 6 g) is for cable90 b (FIG. 8) winding counter-clockwise and groove section 163 (FIG. 6g) is for cable 90 a (FIG. 8) winding clockwise.

The tensioning screw 96 a inserts into hole 144 a of output pulley 20,which sits on the shoulder 145 a (FIG. 5 d) that supports the tensioningscrew 96 a under loading from the counter-clockwise auxiliary cable 90b. The cable 90 b accesses the output pulley 20 through the lateral hole147 (FIG. 5 f), wraps around the tensioning screw 96 a for up to threewindings, and passes through the hole 154 (FIG. 9 a) of the tensioningscrew 94 a. It is noted that the only difference among screws 94 a, 94b, 96 a and 96 b is the axial location of hole 154. There are twolateral holes 147 on the output pulley 20 for each of the tensioningscrews, the choice between the pair will determine the direction ofcable winding on the tensioning screws and thus the direction ofrotation of the tensioning screws for tightening their respective cable.Turning setscrew 97 (FIG. 11 b) in tapped hole 159 (FIG. 9 b) of thetensioning screw pinches the cable 90 b and deforms the tip of the cable90 b until it is jammed inside the hole 154 and secured by the setscrew97. To allow room for maneuvering the cable 90 b, the entire subassemblyof tensioning screw 96 a and the setscrew 97 is taken outside of theoutput pulley 20 after threading the cable through the lateral accesshole 147 to complete the cable windings and setscrew securing beforebeing put back to the hole 144 a.

Once the cable 90 b and the tensioning screw 96 a are inside hole 144 a,the cable tension can be adjusted by turning the tensioning screw 96 aclockwise by means of a screwdriver engaging at the slot 158 of thetensioning screw (FIG. 9 b). After the desired cable tension is reacheda washer 99 (FIG. 1) and hex nut 100 (FIG. 1) are placed onto thethreaded section 156 (FIG. 9 b) of the tensioning screw 96 a to fix therotary position of the tensioning screw 96 a with respect to the outputpulley 20. The cable tension can be guaranteed if the tensioning screwcannot be turned counter-clockwise without loosening up the hex nut.This is accomplished by selecting the lateral access hole 147 from thepair for each tensioning screws on the output pulley 20 such that thetensioning screw will always need to be turned clockwise to tighten thecable tension.

Specifically, if the tensioning screw attempts to turn counter-clockwisedue to the cable tension, the washer and hex nut will attempt to rotateas a unit with respect to the output pulley but friction against thefront face of the output pulley will resist the rotation and thus anyrotation of the tensioning screw 96 a will be done with the washer 99and hex nut 100 remaining static to the output pulley 20, resulting inthe hex nut compressing against the output pulley via the tensioningscrew and consequently resisting any further counter-clockwise rotationof the tensioning screw 96 a. Provided the friction against between theoutput pulley front face and the washer 99 and the hex nut 100 isgreater than that between the internal thread of hex nut 100 and theexternal thread section 156 of tensioning screw 96 a (of FIG. 9 a), thecable tension will not loosen up on its own. This can be ensured by thelarge surface area of the flat washer 99, with which the tensioningscrew 96 a, the washer 99 and the hex nut 100 will not rotatecounter-clockwise as a unit, thereby guaranteeing the tensioning of thatparticular cable section. The load carried by the right-angle drive ismounted to the front face of the output pulley 20, via the bolt holes150 and the timing dowel holes 151, shown in FIGS. 5 a and 5 b. Tolocate the center-of-rotation of the output pulley 20, the load can usethe center dowel 32 of FIG. 1. FIG. 5 e shows details of the tensioningmechanism at output pulley 20.

The flexible cables 90 b and 92 b may be low-stretch/pre-tensionedcables, which may or may not be metallic, to minimize transmission lossdue to elastic stretching of the cables.

Referring again to FIG. 2, the idler mechanisms each include main idlers80 a and 80 b, and auxiliary idlers 82 a and 82 b, and it is noted thatmain idlers 80 a and 80 b and auxiliary idlers 82 a and 82 b may or maynot be identical depending on the relative position of the idler shaft78 with respect to both the input pulley 54 and output pulley 20, andauxiliary idler spacer 84 that separates the main idlers 80 a, 80 b andauxiliary idlers 82 a, 82 b, and two flange radial ball-bearings 86 toallow free rotation of both the main idlers 80 a, 80 b and auxiliaryidlers 82 a, 82 b independent of each other. FIGS. 7 a and 7 b show theidler shafts 78 which include a circumferential ridge 79 located nearone of the ends of the shaft 78 so that the two shafts are inserted intoholes 76 a distance equal to the distance from that particular end tothe ridge 79, best seen in FIG. 10 c. A lock nut 60 is located betweenthe output pulley 20 and the angular-contact ball-bearing 24 locatedclosest to the output pulley 20 for retaining that particular bearing inmid-housing 22, see FIG. 4 f.

FIG. 8 shows the relative positions of the input pulley 54 and theoutput pulley 20. The idler shafts 78 are located in holes 76 of section74 of mid housing 22, best seen in FIGS. 2 and 4 a. In the cable-drivenright-angle drive, the input axis 58 defined by the harmonic-drive 56(see FIG. 15) and output axis 180 defined by the output shaft 26. (FIG.11 b) are aligned perpendicular to each other. The transmission betweenthe input and output pulleys 54 and 20 respectively is carried out bythe cable-pulley system including input pulley 54 and output pulley 20,main idlers 80 a, 80 b and auxiliary idlers 82 a, 82 b and cables 90 a,90 b and 92 a, 92 b, in which these two sets of cables correspond to thetwo directions of rotation.

Referring to FIG. 8, (and FIG. 11 a for the tensioning screws referredto below) there are a total of four independent cable sets including: 1)auxiliary cable 90 a responsible for clockwise rotation of the outputpulley 20 which is associated with auxiliary idler 82 a and auxiliarytensioning screw 94 a; 2) auxiliary cable 90 b which is responsible forcounter-clockwise rotation of the output pulley 20 which is associatedwith auxiliary idler 82 b and auxiliary tensioning screw 96 a; 3) maincable 92 a which is responsible for clockwise rotation of the outputpulley 20 which is associated with main idler 80 a and main tensioningscrew 94 b; and 4) main cable 92 b responsible for counter-clockwiserotation of the output pulley 20 which is associated with main idler 80b and main tensioning screw 96 b. Each cable can be independentlytensioned, but when used to transmit rotational motion between the inputand output shafts the main and auxiliary cable pairs work together foreach direction to reduce tension in each cable set. The two sets ofcables reduce the cable tension to improve cable reliability and provideredundancy to improve safety should one cable break.

Referring again to FIG. 8, when the input pulley 54, driven by theoutput flange 98 of the harmonic-drive 56, rotates counter-clockwise(when looking at the back of the harmonic-drive 56), thecounter-clockwise main cables 92 b and auxiliary cable 90 b are undertension from the end through the lateral access holes 141 b, 141 a (FIG.6 a) respectively with the terminations at the crimped fittings 101situated inside the pockets 138 a, 140 a respectively on the inputpulley 54, being diverted into a right-angle change of direction by themain idlers 80 b and auxiliary idlers 82 b, and pulls on other end ofthe cables at the setscrew 97 termination (FIG. 5 e) on the maintensioning screws 96 b and auxiliary tensioning screws 96 a and hencecause the output pulley 20 and dowel 32 connected to output shaft 26 torotate counter-clockwise looking at the front face of the output pulley20. Whereas the other set of cables unwind in the opposite directionsince clockwise main cable 92 a and auxiliary cable 90 a, beginning atthe input pulley 54 at the crimped fittings terminations 101 through thelateral access holes 141 d and 141 c (FIG. 6 a) respectively, arediverted into a right-angle change of direction by the main idler 80 aand auxiliary idler 82 a, and are terminated on the output pulley 20 atthe setscrew 97 on the main tensioning screws 94 b and auxiliarytensioning screws 94 a.

Cables 90 a, 90 b and 92 a, 92 b are preferablylow-stretch/pre-tensioned cables to minimize motion loss due to elasticdeformation of the cables under tension. Referring to FIGS. 1, 2, 10 band 10 c, when assembled, idler caps 62 and 64 are bolted to the top andbottom of housing cover 16 which support the idler shafts 78 on theirfree ends opposite to those at the holes 76 on the mid-housing 22. TheIdlers 80 a, 80 b and 82 a, 82 b mounted on the idler shafts thus canmaintain their radial positions with respect to the input pulley 54 andoutput pulley 20 even when the cables are under tension.

FIG. 13 shows a view from the back of the drive unit opposite to theoutput face from which dowel 32 projects. As can be seen, bearing 59rotates in hole 61 (of FIG. 2) located in the back wall of chassis 14.

FIGS. 14 and 15 show isometric views of the drive unit without the cover16 thereby showing the placement of the cable drive system, shown inFIG. 8, now placed in the chassis 14. There is a slight difference instructure of the output pulley 20 of the right-angle drive in FIGS. 14and 15 compared to right-angle drive 10 in FIG. 1. In FIGS. 14 and 15,the output pulley 20 includes a raised guide 21 integrally formed on theouter surface of pulley 20. The right-angle drive shown in FIGS. 14 and15 is larger than the right-angle drive 10 in FIG. 1 because it is usedin both the shoulder-pitch joint as the right-angle drive 406 and theelbow-pitch joint as the right-angle drive 410.

The load at the elbow-pitch and shoulder-pitch joints are substantiallyhigher than that at the wrist-pitch joint due to the difference incomponent weight each joint is carrying, hence the pulleys 20 and 54need to be enlarged to compensate for the higher torque so the stress inthe driving cable sets 90 a, 90 b, 92 a, 92 b can be reduced. Thus theoverall size of the right-angle drive 10 in FIG. 1, while applicable tothe wrist-pitch joint, is required to be increased as a result for theelbow-pitch and shoulder-pitch joints to become the variation shown inFIGS. 14 and 15. The excessive loading at the shoulder-pitch jointcompared to that at the elbow-pitch joint is partially compensated forby the counterbalance torsion spring 440 as shown in FIG. 18 d.Referring to FIG. 18 d, the raised guide 21 on output pulley 20 ofright-angle drive unit 406 is used for guiding the internal axle 505 ofthe shoulder support 439 to be coupled with the output pulley 20,forming a combined drive shaft to rotate the output bracket 266. Theraised guide 21 on the output pulley 20 of the right-angle drive unit410 for the elbow-pitch joint is not used (FIG. 19 e).

The cable driven right-angle drive 10 disclosed herein has severaladvantageous features. Specifically, it is a low-to-medium load,lightweight unit which may be retrofitted into the joints of existingmodular robotic arm systems. The use of the drive cables 90 a, 90 b and92 a, 92 b provide a backlash-free bidirectional rotation. The drive, byincorporating harmonic-drive 56, provides a back-lash free motor input.The drive unit is compact and lightweight, and has an in-line or offsetinput/output configuration. In an in-line configuration the input andoutput axes are coplanar whereas in an offset configuration the planesof the input and output axes are parallel but offset in direction normalto the planes. The relative alignment error between the input and outputaxis can be compensated by the tensioning of the cables. The unit usesredundant cables for safety, uses a simple cable tensioning mechanismand is highly cost-effective since it is of simple construction and doesnot require expensive gearing and alignment.

In another embodiment of the pulleys 20 and 54, both the input andoutput pulleys can have any number of differential diametrical sectionsother than the two shown for this design. Provided there would be a pairof idler pulley subassembly to go with each section of cabletransmission, more sections of cable transmission can be introduced tothe input and output pulleys as long as the other physical constraintsare satisfied. Additional sections of cable will provide more securityto the overall integrity of the transmission, but the size of the modulewill inevitably be increased.

A gear ratio may be introduced using a miniature harmonic gear locatedat the input pulley, and the load is mounted directly on the front faceof the output pulley. Additional devices such as angular motion sensorsand motor brakes may be fitted onto the output pulley drive shaft tomake a compact module. The module can be sized to the targeted loadcapacity using off-the-shelf components readily available in varioussizes from multiple vendors.

Thus, the present invention provides a compact yet highly efficientmodule for right-angle transmission by combining cable-pulley systemsand harmonic drive technology. The cable-pulley drive system provideshigh fidelity while the harmonic drive contributes to the high powerdensity and back-drivability. In light to medium duty load applications,this module will enable miniature actuators and sensors whileoutperforming conventional bevel or worm gearing. The mechanism itselfis simple yet robust, highly modular and flexible in interfacing.Redundant cables add safety to the design and the accessibility of theinput and output transmission axes facilitate integration of auxiliarydevices into a compact integrated unit. The design has simple componentsand does not need expensive gear cutting technology. No other existingtechnology can compete in terms of positional accuracy, size and weight,efficiency, modularity, ease of reconfiguration, integration andmaintenance.

Thus, the present invention provides a right-angle drive which exhibitslittle or no backlash, simple and robust design, highly repeatableprecision, high efficiency, back-driveability, a high gear ratio,compact size and lightweight for a right-angle drive.

While a preferred embodiment of the present invention is the right-angledrive where the input pulley 54 and output pulley 20 rotate in planesthat are perpendicular to each other so that the rotational motion ofthe input shaft is converted to rotational motion about an axisperpendicular to the input rotational axis, it will be understood thatother angles are possible. Particularly, the housing chassis 14, cover16, mid-housing 22 and the other components can be made to accommodateany fixed angle between the input and output axis as long as the cablerouting is not compromised. Thus, while the preferred nominal anglebetween input and output is 90 degrees, it will be appreciated thatother angles are possible. In addition, because flexible cables arebeing used in which the tension can be adjusted, it will be appreciatedthat the user can reconfigure the housing to adjust the input and outputaxis at the preferred angle so that as the input and output pulleys arelocked in position to give the desired angle, the cable tension of eachcable is adjusted accordingly to either take up the slack in the cablescaused by repositioning the input and output pulleys with respect toeach other.

For example, one method to facilitate tensioning of the screws fordifferent angles is to have the tensioning screws continuously torquedby a built-in spring. The screw may also have a ratchet to preventcounter-rotation of the tension screw making the rotationunidirectional. Therefore any “slack” in the cable may be removed by thespring and the ratchet prevents further slackening. The spring isselected to have sufficient torque to tension the cable adequately. Thespring or a ratchet can both provide cable tensioning, regardless ofwhether the input and output pulleys are configured for right-angletransmission or some other angle. With a spring, the cable is constantlyunder tension without any manual adjustment, but a very strong spring ispreferred for tensioning. A ratchet mechanism also gives unidirectionalrotation, that is, the direction to further tighten the cable tension,such that it is guaranteed no cable loosening will happen under normalcircumstances.

A difference between a ratchet tensioning mechanism and the cabletension mechanism shown in FIG. 5 e, is that the ratchet mechanism is adiscrete system, meaning that the number of “locking” rotary positionsthe screw can sit at depends on the number of teeth on the ratchet,whereas the screw/nut tensioning mechanism illustrated in FIG. 5 e hasan infinite number of positions possible for “locking” purpose once thecable tension is set. The screw/nut tensioning requires manualadjustment, whereas automatic tension adjustment is possible using aratcheting mechanism. Thus spring or ratchet or screw/nut mechanisms areall possible embodiments of the cable tensioning device.

2) Surgical Manipulator

FIGS. 16 a to 21 e show the surgical manipulator arm 400 in its entiretyand all the various components making up the arm. FIG. 16 a shows anisometric view of a six degrees-of-freedom surgical robot showngenerally at 400 forming part of the present invention. FIGS. 16 a and16 e show two different isometric views of manipulator 400 while FIGS.16 b, 16 c and 16 d show back, side and top views respectively ofmanipulator 400. The basic exterior structure of manipulator 400 will bediscussed with respect to FIGS. 16 a to 16 e and details of the internalstructure of each of these components will be discussed with respect toFIGS. 17 a to 21 e.

Referring to FIG. 16 a, the base 401 of the surgical robot 400 containsthe shoulder-roll joint with axis 414 and part of the shoulder-pitchjoint with axis 422. Referring to FIGS. 17 a to 17 e, manipulatorshoulder base 401 includes a mounting plate 200 for table-topinstallation, a support housing 202 mounted on base plate 200 for boththe shoulder-roll and shoulder-pitch joints, and a driven spur gear 204for rotation about axis 414 (also shown in FIG. 16 a) which togetherwith shoulder-pitch housing 252 (FIG. 17 c) form part of theshoulder-pitch joint (refer to description in the next paragraph). Theshoulder-pitch housing 252 is mounted inside support housing 202 by apair of angular-contact ball bearings 500, with an optical encoder 503coupled to the extension 258 of the housing 252 to measure theshoulder-roll joint output position. Straight-tooth spur gear 204 isrotationally driven by a smaller-sized pinion 206 with which it ismeshed. The pinion 206 is an anti-backlash gear with springs 216 thateliminates gaps between mating gear teeth when meshing with the drivengear 204. Via the hub 214 and subsequently the shoulder-roll drive shaft220, pinion 206 is mounted to, and driven by, a motor 212 mounted belowgear 206 and secured to housing 202. A gear ratio exists between thegear 204 and pinion 206 which depends on the difference in theirrespective diameters. The motor 212 is a combination of harmonic-drive,an optical incremental encoder (measuring input motor position) and a DCbrushless motor. The harmonic-drive 56 supplies additional gear ratiobetween the motor 212 input to the resulting output motion at the driveshaft 220 to further reduce the speed of the gear 204.

Referring to FIG. 17 c in particular, to provide fail-safe braking, apower-off brake 208 is coupled to the motor 212, at which the armatureof the brake 222 is connected to the shoulder-roll drive shaft 220 justbelow the motor 212. The brake 222 is mounted onto the brake support210, which is then secured on the mounting plate 200. Upon braking oremergency stop situation, power supplied to the brake 208 will be cut,the armature 222 of the brake 208 will stop rotating by the magneticfield generated inside the brake 208, and thus the drive shaft 220 willcease all motion and the entire shoulder-roll joint can be stopped as aresult.

Motor 212 may include a servo motor integrated with a harmonic gear andan angular encoder for measuring rotational displacement of the motorshaft 220 coupled to said pinion gear.

Referring to FIGS. 18 a to 18 e, the shoulder-pitch joint includes aright-angle drive 406 which is mounted on top of upper base 404 (FIG. 16a). The structure and operation of the right angle drive shoulder-pitchjoint 406 has been described above in the section entitled Right-AngleDrive. The spur gear 204 and the shoulder-pitch housing 252 form part ofthe shoulder-roll structure, as described in the previous paragraph.Referring to FIG. 18 d, the spur gear 204 acts as the interface betweenthe right-angle drive 406 and the input actuating components, whichinclude a DC brushless motor 250, with an interface plate 253 at therear at which a power-off electromagnetic brake 254 is attached, and anincremental optical encoder 256 mounted to the brake 254 directly whichmeasures the motor input position.

Upon braking, the power-off brake 254 will act in a similar fashion asits counterpart in the shoulder-roll joint in that the motor 250rotation will be stopped via the connected rear end of the motor outputshaft. The front end of the output shaft of the motor 250 is connectedto the harmonic-drive 56 of the right-angle drive 406, which rotates theinput pulley 54 and drives the output pulley 20, as described in theRight-Angle Drive section. At the output side of the right-angle drive406, the shoulder support 439 is mounted to the chassis 14 of the drive406, which has an internal axle 505 supported by a pair ofangular-contact ball bearings 504 and coupled with the output pulley 20of the right-angle drive 406. At the outside end of the axle 505, amounting bracket 266 is mounted, at which the lower arm of themanipulator 408 is attached to, resulting in the lower arm 408 (FIG. 16a) rotating about the shoulder-pitch axis 422.

To assist the motor 250 in moving the lower arm 408 and the remainingcomponents attached above it about the shoulder-pitch joint againstgravity, a torsion spring 440 (FIGS. 16 a, 18 b and 18 e) is mounted onthe shoulder support 439 and the lower arm 408 which serves as acounterbalance as the lower arm 408 rotates in the indicated directionabout the shoulder-pitch axis 422. Referring to FIGS. 18 b, and 18 e inparticular, the counterbalance spring 440 has one leg supported by abracket 507, while the other leg rotates together with the lower arm 408(seen in FIG. 16 a). The spring 440 will be loaded only when the lowerarm 408 is rotating forward, as illustrated along the direction of thearrow in FIG. 18 e. All components attach to bracket 266 rotates as aunit about axis 414 (seen in FIG. 16 a) for the shoulder-roll joint.

Referring to FIGS. 16 a, 16 e, 19 a to 19 e, attached to the upper endof the lower manipulator arm 408 is an elbow-pitch right-angle drive 410of the same structure and operation as that of the shoulder-pitch jointas described in the previous paragraph. An upper arm 412 is mounted tothe bracket 282 on top of the output pulley 20 (FIG. 19 e) of theelbow-pitch joint right-angle drive 410 so that the rotational motion ofthe input pulley 54 (FIG. 19 e) to the drive unit 410 is translated intorotational motion of the upper arm 412 about the elbow-pitch axis 426.As seen in FIG. 19 e, a DC brushless motor 460, an interface plate 462with the power-off brake 464, and the incremental optical encoder 466residing inside housing 280 are identical to their counterparts in theshoulder-pitch joint 250, 253, 254 and 256 respectively (FIG. 18 d) bothin configuration and operation.

Referring to FIGS. 16 a, 16 e, 20 a to 20 e, attached to the upper endof the manipulator fore arm 412 is a wrist-pitch right-angle drive 416of similar structure and operation as that of the elbow andshoulder-pitch joints but smaller in size. A wrist 420 (FIG. 16 a) ismounted to the bracket 288 on top of the output pulley 20 (FIG. 20 c) ofthe wrist-pitch joint right-angle drive 416 so that the rotationalmotion of the input pulley 54 (FIG. 20 c) to the drive unit 416 istranslated into rotational motion of the wrist 420 about the wrist-pitchaxis 432. The internal configuration of the fore arm 412 is similar tothat of the lower arm 408, in which the DC brushless motor 470,interface plate 471 with the power-off brake 471 residing inside housing286 are similar to their counterparts 460, 462 and 464 of the lower arm408 but smaller in size and having the same operating principle. Theincremental encoder 473 is identical to the encoder 466 of the lower arm408.

Referring now to FIGS. 21 a to 21 e and particularly FIG. 21 e, wristunit 420 includes a housing 300 containing an actuation mechanism whichincludes a motor 302, interface plate 480, brake 304, encoder 306 beingconfigured to operate in the same way as their counterparts 470, 471,472 and 473 in the wrist-pitch joint assembly described in the previousparagraph. The actuation mechanism within wrist 420 also includes thewrist output shaft housing 424 which encloses a harmonic-drive 482identical to that of the wrist-pitch right-angle drive 416, an outputshaft 484 at the outside end of which the end-effector 428 is connected,and an incremental encoder 483 which is identical to encoder 46 in FIG.20 c being used in the wrist-pitch right-angle drive 416. Theend-effector 428 is driven by the actuation mechanism, specificallymotor 302 to rotate about the wrist-roll axis 438 via the gear-reductionby the harmonic-drive 482.

Thus the six degrees-of-freedom of the manipulator are all accountedfor: shoulder-roll axis 414, shoulder-pitch axis 422, elbow-pitch axis426, wrist-pitch axis 432, wrist-roll axis 438 and tool-yaw axis 441(which will be discussed in detail in the Surgical End-Effector Sectionhereinafter). The linkages of the manipulator 400 are arranged in anoffset configuration in which the lower arm 408 and the fore arm 412 areboth cascaded along the shoulder-pitch 422 and elbow-pitch 426 axis withrespect to the shoulder-roll axis 414 and wrist-roll 438 axis. Thisconfiguration allows for a wider range of travel for all the pitchjoints when accommodating for the minimum length of the manipulator arm(formed by 408, 412, 424 and 428) required to enclose the entireactuation unit for each joint given a certain desired linkage lengthfrom joint-to-joint.

The exact amount of offset of both the lower arm 408 and upper arm 412is adjusted by the length of the section 506 (FIG. 18 d) of the shouldersupport 439 along the direction of shoulder-pitch axis 422, and theresulting offset locates the wrist 420 such that the wrist-roll axis 438is aligned with that of shoulder-roll axis 414. The reason for this liesin the kinematic consideration which calls for an in-line kinematicchain for more intuitive control and also for simplified kinematicscomputation. By aligning the wrist-roll 438 and shoulder-roll 414 axes,the in-line kinematic configuration is achieved even though the physicalmanipulator is in an offset arrangement.

3) Surgical Tools

The end effecter 428 (FIG. 16 a) connected to the end of the roboticwrist unit 424 holds a surgical tool 430 which can be detached from theend-effector 428 in a manner to be discussed after the discussion of thetools. FIGS. 22 a to 22 e show a first embodiment of a surgical tool 430which can be detachably mounted to end effecter 428 attached to themanipulator 400 (FIG. 16 a). Referring to FIGS. 22 c and 22 d, tool 430includes a main housing 500, a Teflon bushing 502 seated in the end ofhousing 500, a piston 504 sliding in housing 500 through Teflon bushing502, a right hand forcep blade 506, a left hand forcep blade 508, and aforcep insert 510. The two forcep blades have a hole through them and adowel 512 is inserted through the holes and the two blades pivot aboutthis dowel 512 as the piston 504 moves in and out of main housing 500.Piston 504 includes a head portion 514 located at the outer end of thepiston and a narrower neck 516 located between the head portion 514 andthe rest of the body of the piston 504. Piston 504 includes a smallerdiameter extension 522 which slides up and down between the end sectionsof the two forcep blades 506 and 508 which are located inside mainhousing 500 above the dowel 512. An O-ring 520 is seated at the end ofthe larger diameter section of the piston 504. Tool 430 includes atiming pulley 528.

FIGS. 23 a and 23 b show another embodiment of a surgical tool showngenerally at 560 which includes a main body 562, a piston 564 having apiston head 566 separated from the body of the piston by a neck 568. Thetwo forcep blades 570 and 572 pivot about a common pivot point locatedinside housing 562 and use a spring 574 to return the blades 570 and 572to its open position. The spring 574 is contained in housing sections580 and 582 associated with blades 570 and 572 respectively. The tooluses an internal wedge action to close the blades 570 and 572. Thedriving piston 564 uses a roller 576 (FIG. 23 b) to separate the upperproximate portion of the blades above the pivot point, which in turnsqueezes the distal blade tips together which engage tissue duringsurgery.

FIGS. 24 a and 24 b show another embodiment of a surgical tool whichincludes a main body 632, a central piston 634 having a piston head 636separated from the body portion by neck 638. Surgical tool 632 uses a4-bar linkage, creating a scissor motion, to actuate the forcep blades640 and 642.

FIGS. 25 a and 25 b show another embodiment of a surgical tool 700 whichagain includes a main housing 702, a center piston 704, and forcepblades 708 and 710, made from a single piece. The forcep blades 708 and710 are either made in a single piece or two pieces welded together sothat opening of the blades is carried out by the spring force at thejoint of the two blades. To close the blades the piston 704 translatesdownwards and with a wedge cut into it, it closes the blades 708 and 710by elastically deforming the material where the blades 708 and 710joint.

It will be understood that there are numerous types of surgical toolseach having a tool portion which may be of different structure andfunction (eg. Scissors, scalpels, forceps, etc.) that may be mounted tothe end-effector 428 and regardless of the structure or function ofthese different tool portions when the piston 504 is linearly retractedor linearly extended with respect to said end-effector 428 the toolportion of the surgical tool 430 may be activated. The forceps shown isonly exemplary and non-limiting.

4) Surgical End-Effector

As mentioned above, with reference to FIG. 16 a, the end effecter 428connected to the end of the robotic wrist unit 424 with the exchangeablesurgical tool 430 held. Microsurgical manipulators preferably requireend-effectors that are small and lightweight, use different tools, have2 degree-of-freedom (DOF) actuation, enable fast and automated toolexchange, have 6 DOF tool tip force sensing, have tool clasp forcesensing, maintain a sterile barrier between the robot and the tooland/or patient, and easy to assemble.

The end-effector 428 is comprised of both sterile and non-sterilecomponents. Sterile components are exposed to the working atmosphere ofthe surgical worksite and are not guarded by a bacteria resistant bag inwhich the non-sterile components of the end-effector 428, and subsequentremaining arm, are protected. Therefore, sterile components are requiredto be contamination free by the auto-claving process, using highpressure and temperature steam, after each surgery. In order to separatecomponents on the end-effector 428 that are in direct contact with thesurgical environment (and surgical tool 430) a sterile barrier needs tobe established.

The size requirement of the end-effector 428 is preferably that it besmaller than the typical human hand and as lightweight as possible, thusdriving the overall size of the entire arm. FIG. 26 a shows an isometricview of the end-effector 428 assembled holding the surgical tool 430.Also, the end-effector 428 preferably is sized/orientated accordingly soas to provide maximum visibility at the tool tips and the work site. Inorder for this to be achieved, the actuator responsible fortool-actuation is preferably located away from the surgical site. Thisasymmetrical orientation facilitates two end-effectors being positionedclosely to allow small workspaces in a dual-manipulator operatingconfiguration to be discussed hereafter.

In a non-limiting embodiment of the surgical manipulator, an overallsize of the end-effector 428 (not including the surgical tool) has alength, width and height of: 70 mm×50 mm×80 mm respectively and a weightof 240 g. These parameters satisfy the size requirements of theend-effector 428, but are exemplary only and not intended to belimiting.

Presently available surgical systems are known to have numerous sterilesub-components and offer a complex means of assembly, causing longexhaustive set-up times. The end-effector 428 disclosed hereinadvantageously offers minimal assembly components and a set-up time inminutes.

Referring to FIGS. 26 a, 26 b, 26 c, 26 d, 26 e and particularly FIG. 26b, end-effector 428 includes a main assembly 436 which constitutes thenon-sterile member. This is where a protective bag or hard guarding willencapsulate the end-effector 428. End-effector 428 also comprises threemain sub-components, including a magnetic tool holder 450, tool actuator452, and tool-yaw mechanism 454. All these subassemblies have a simpleinterface to the main assembly 436 for ease of set-up by a nurse. Theexploded view in FIG. 26 b shows how the sterile components are removed.These three sub-components, magnetic tool holder 450, tool actuator 452,and tool-yaw mechanism 454 are located and releasably secured to themain assembly 436 by threaded quick change pins 458, 460 and 462.

For a safety requirement, the surgical tool 430 must have the ability tobe manually extracted from the workspace from the top during anemergency. This can be achieved by removing both the magnetic toolholder 450 and tool actuator 452 quick pins 458 and 460 respectively,sliding out the tool actuator 452 and then vertically removing the toolholder 450 containing the surgical tool 430. Another, quicker way wouldbe to manually eject the tool 430 from the tool holder 450 (discussedlater) and on a slight angle from vertical, so as to clear the toolflange, extract the tool 430 from the surgical site.

Each of the main assembly 436, and magnetic tool holder 450, toolactuator 452, and tool actuator 452 will be discussed in more detailherebelow.

a) Main Assembly 436

Referring to FIGS. 27 e and 27 f, the main assembly 436 of theend-effector 428 includes all the electronic components, the tool-yawmotor 600, the tool-actuation motor 601, the tool-tip force-momentsensor 608 and the tool-actuation force sensor 604 all mounted onend-effector 428. This forms the core of the end-effector 428 wherethese components and their adjacent supporting structures are consideredto be non-sterile and thus need to be protected by a drape bag. Thedrape bag will need to cover from the base of the robot all the waythrough the entire length of the arm until the front face 611 of theend-effector main assembly 436, whereas the remaining subassemblies ofthe end-effector will be attached to the main assembly via theircorresponding interfaces pinching through the drape bag.

Referring in particular to FIG. 27 f, the tool-yaw motor 600 is mountedonto the motor-support bracket 602, which is an inverted C-shapestructure clamping onto both ends of the tool-yaw motor 600. A squaredrive shaft 609 is attached to the output shaft of the tool-yaw motor600 which is exposed to the bottom side of the motor-support bracket602, at which point the drive timing pulley (discussed in a laterparagraph) of the tool-yaw subassembly 454 is connected to the squaredrive shaft 609 for rotation transmission to the tool-yaw axis 441.

Referring to FIGS. 26 e and 27 e, the tool-actuation motor 601 isattached to the motor-support bracket 602 at a lateral extension,arranging the motor 601 in parallel to the tool-yaw motor 600. Thismotor 601 is a linear actuator, in which its output shaft moves up anddown along the major axis of the motor itself, and at the end of whichthe angled actuator bar 603 is connected. The bar 603 can thus transmitthe vertical motion to the tool actuator subassembly 452 which ismounted at the other end of the bar 603. The actuator subassembly 452,upon engaging with the tool-actuation interface (will be discussed in alater paragraph), provides the tool-actuation axis of motion for theend-effector.

Referring to FIG. 27 f, the tool-tip force-moment sensor 608 is thesingle mechanical linkage between the motor-support bracket 602 and thebase block 605 which interfaces back to the wrist of the robot arm. Thisis to ensure all of the interactive force and moment at the tool tip istransmitted through the sensor 608 only and back to the base block 605with no alternative load paths (will be discussed in a later paragraph).This load path is shown by the arrows in FIG. 27 a. The base block 605has a clearance hole 612 through which the tool-yaw motor 600 is passedthrough without physically contacting any part of the base block 605.The tool-holder subassembly 450, and subsequently the tool 430, isattached to the front face 611 of the motor-support bracket 602. Thus itmeans except for the base block 605, the remaining components of theentire end-effector are supported at a single interface at the frontface of the force-moment sensor 608, see FIG. 26 b.

Referring again to FIG. 27 f, the tool-actuation force sensor 604 ismounted on the angled actuation bar 603 between the point where the bar603 is supported by the vertical guide rod 606 and the interface 607with the tool-actuator subassembly 452. The sensor 604 takes the form ofa strain gauge, at which point on the bar 603 the elastic verticaldeflection due to the tool-actuation can be measured (as will bediscussed in a later paragraph).

b) Tool-Actuation Mechanism 452

Referring to FIG. 26 d, the end-effector 428 includes the tool-actuationmechanism 452 that works completely independent from tool yawingmechanism 454 discussed hereinafter. This is achieved using a linearguide support 606 which is coupled to a linear actuator 601 tovertically translate the piston 504 of the surgical tool 430 via thenarrow neck section 516 along the tool axis to provide a gripping motionbetween the two blades 506 and 508 (FIGS. 22 c and 22 d). This featureof the end-effector 428 can be utilized whether the tool 430 is rotatingabout the tool-yaw axis 441 (FIG. 16 a) or static due to the circularneck section 516 of the tool piston 504. It can also be bypassed whenusing a surgical tool that doesn't require actuation (e.g. probe,scalpel, cauterizer etc.), with the only requirement being the tool doesnot possess any mechanical interface to couple with actuationsubassembly 452 as does the piston 504 of the forcep tool 430.

Referring to FIGS. 28 a and 28 b, the tool actuator mechanism 452 iscoupled to an angled actuation bar 603 by a cross-location pin 460. Themechanism includes a pair of pivoting fingers 614 that are securedaround the piston member 504 of the forcep surgical tool 430. Thesefingers 614 are spring loaded by springs 628 to an engaged position, butcan be passively opened up for tool removal.

Referring to FIGS. 26 e and 27 f, the angled actuation bar 603 is guidedby a linear ball bearing 615 to the offset actuator position. Straingauge 604 located on the angled actuation bar 603 enables the sensing oftool-actuation forces. As the cantilever portion of the bracket exhibitsdeflection, in either direction caused by the reaction as a result ofthe up and down motion of the piston 504 of the tool 430, the straingauge 604 will generate a voltage signal which will be fed back to thecontroller for interpretation. With proper calibration of the straingauge sensor 604, the vertical force required to actuate the tool can bedetermined, which can then be translated into a pinching force at thetip of the blades 506 and 508 of the tool 430 (FIG. 22 c) given thegeometric profile of the cam section 510 of the blades 506 and 508 thatare responsible for the closing of the blades 506 and 508 upon theupward sliding of the extension 522 of the piston 504 in between theblades 506 and 508. Refer to the arrows in FIG. 26 d for an illustrationof how the pinching force at the tips of the blades 506 and 508 isdetected by the strain gauge 604.

c) Magnetic Tool Holder 450

The purpose of the magnetic tool holder 450 is to hold the tool rigidly,but still allowing the tool to rotate easily. This is accomplished byconstraining the tool 430 in a support body 616, which in a non-limitingexemplary embodiment shown in FIG. 29 c is a generally ‘V’ shaped blockmade from ABS plastic having an elongate channel having a size suitablereceive therein the cylindrical tool body 500 of surgical tool 430,which allows the tool 430 to rotate within support body 616 with minimalfriction. Referring to FIGS. 26 b, 29 a and 29 b, the tool body 500 ofthe surgical tool 430, preferably made from 400 series stainless steelwhich is magnetic, is seated in the ‘V’ block 616 by two rare earth potmagnets 618 imbedded in the ‘V’ block. The magnetic force and ‘V’ blockreaction forces tangential to the shaft secure the tool 430 radially,whereas flanges 529 on the body 500 of the surgical tool 430 locates andconstrains the tool axially (FIG. 22 a), due to a close axial fit withthe ‘V’ block body 616. FIGS. 29 c to 29 e show more detailed views ofthe magnetic tool holder.

Another capability of the tool holder 450 is that it can enable passivetool exchange for automatic tool change-out. Referring to FIGS. 29 c, 29d and 29 e, the ‘V’ block 616 is featured with a tool release mechanismthat once compressed can pivot, similar to a scissor action, to stripthe tool body 500 away from the magnets 618 and eject the tool 430. FIG.29 d shows the tool-engaged configuration, or when the tool-ejectionwings 617 are in closed position. FIG. 29 e, on the other hand, showsthe tool-ejecting configuration, or when the wings 617 are in openedposition. After ejecting the tool, the wings 617 will return to thedefault closed position by the compression springs 619 located at theback of each wing 617 (best seen in FIGS. 29 b and 29 d).

FIG. 29 f shows the passive tool changer mechanism on a tool tray 911for auto tool-changing. Static pins 950, fixed to a tool tray 911 arepositioned to engage specific end-effector features to release the tool.These features include the pivoting fingers 614 of the actuatorsubassembly 452 and the outer idler pulleys 438 of the tool-yawsubassembly 454, both of which are engaging with the tool 430 and needsto be released. The actual ejecting feature, however, lies in thetool-holder 450, from which the ejecting wings 617 need to be pressedbackward into the opened position so as to eject the tool 430. This iscarried out by the mating ejection latches 951 on the tool tray 911,which line up with the wings 617 and has a spring-loaded pliers-likemechanism to provide a cushioned tool-ejection.

The downward motion of the manipulator 400 is the only active componentof this process, in which the end-effector 428 is oriented such that thetool 430 is horizontal when the manipulator 400 pushes down onto thetool tray 911, forcing the end-effector 428 engaging features 614 and438 to be opened up by the pins 950 on the tool tray 911, whereas thewings 617 are actuated by the ejection latches 951, thus releasingcompletely the tool 430 onto the tool tray 911. To pickup a tool, theprocess is reversed. The manipulator 400 brings the empty-handedend-effector 428 over the top of the tool 430 on the tray 911, pressesdown the end-effector 428 to open up the engaging features 614 and 438as well as the ejection wings 617, and captures the tool 430 by themagnet 618 on the tool holder 450 of the end-effector 428. The tool tray911 has multiple sets of pins 950 for each corresponding surgical tool,and also possesses a tool-identification sensor, which upon reading thetag built-in to each tool, the main controller can register which toolthe manipulator 400 has picked up. Identification tags on the tool canbe a bar code or infra-red tag, which works with a correspondingIR-sensor on the tool tray 911.

d) Tool-Yaw Mechanism 454

The end-effector 428 includes a tool-yaw DOF that is actuated by a servomotor integrated with an anti-backlash spur gearhead and an incrementalencoder. Referring to FIG. 26 b, bonded to the output shaft of themotor-gear-encoder combo 600 is the previously described square pin 609that drives a timing pulley 736 from the tool-yaw subassembly 454. Sincethe tool-yaw mechanism 454 is a removable sterile component, aquick-disconnect coupling from the non-sterile servo actuator mainassembly 436 is required. The square pin 609 matched precisely to asquare bore on the drive pulley 736 enables torque to be transmitted tothe tool yaw mechanism 454, but allows easy de-coupling forauto-claving.

Referring to FIGS. 27 a and 27 b, tool yaw mechanism 454 includes aframe 442, and through a pair of idler pulleys 438 mounted thereon, adisposable toothed belt 540 engages a complementarily toothed pulley 528on the surgical tool 430, (see FIG. 26 b) on two opposite ends of thepulley diameter. The toothed belt 540 routing is completed by the middleidler pulley 620 mounted on frame 442 which has the same pitch diameteras the outer idler pulleys 438. The bi-directional rotation of the belt540, driven by the drive pulley 736, converts tangential forces torotary motion on the surgical tool 430. One of the main attributes thatthe tool yaw mechanism 454 exhibits is the passive removal andreplacement of different surgical tools 430. The open front-framedarchitecture and belt configuration allows the tool 430 to beejected/replaced from the front of the tool yaw mechanism 454, avoidingit being tangled around the belt 540. The tool ejection process isfurther aided by the outer idler pulleys 438, supported by sheet metalflexures 621, which can be passively spread out enough to completelydisengage the tool, eliminating any frictional effects. When engagedwith the tool 430, the metal flexures 621 allow a constant preload tothe timing belt 540 during tool yawing but can also manually collapse,when no tool is present, for easy timing belt replacement. FIGS. 27 cand 27 d show further details of components making up the end-effector.

It will be appreciated by those skilled in the art that the end-effector428 disclosed herein may be retrofitted onto any robotic arm assemblyand is not restricted to being mounted on manipulator 400 disclosedherein.

Similarly, it will be appreciated by those skilled in the art that theright-angle drive unit 10 disclosed herein may be used in anyapplication requiring conversion of rotational motion along one axis torotational motion along another axis and is not restricted to beingmounted on manipulator 400 disclosed herein.

Haptic Feedback

In order for the surgeon to retain the sense of touch at the handcontroller during a telerobotic operation, haptics is required whichmeans the end-effector must be capable of providing realistic externalforce and torque sensing at the tool tips and reflecting back to thehand controller. To obtain accurate haptic feedback, the end-effector isadvantageously designed so that forces and torques (moments) at the tooltips are directly registered by the force-moment sensor 608, whichmeasures force and moment through elastic deflection in the direction ofinterest. The sensor 608 needs to measure the force and moment in allsix directions, so that a full 6 DOF haptic feedback can be achieved. Itneeds to have sensing precision within the range of soft tissueinteraction, which is roughly 1 to 200 g. The size of the sensor 608 ispreferably compact enough to be incorporated into the end-effectordesign without enlarging the overall end-effector size to an undesirablescale. Given these parameters, the smallest force-moment sensorpreferred in the present manipulator is the Nano17 of ATI IndustrialAutomation, having an overall size of just ø17 mm×14.5 mm long.

The location of the force-moment sensor 608 within the end-effector 428is important as it determines the eventual precision of the hapticfeedback. Ideally, the sensor 608 should be right at the tool tip wherethe external forces and moments are exerting when the tool is in contactwith a foreign object. In practice this is difficult to achieve as itwill mean having a delicate electronic component build-in to thesurgical tool, which needs to go through auto-claving cycles forsterilization. Also, various tools need to be fitted onto theend-effector 428, thus electronic interfacing is required upon changingof tools which add to the complexity of the end-effector design.Furthermore, sensors on each tool will significantly increase the costof tool production and subsequently the investment on the overall systemby the customers.

Therefore, it is beneficial to keep the miniature force-moment sensorwithin the end-effector but close to the surgical tool. This willminimize the amount of weight on the free end of the sensor so as toavoid saturating the sensing capacity of the sensor. Also by reducingthe physical distance between the tool tips and the point of sensing,signal distortion throughout the load path due to mechanicalimperfections, such as backlash, compliance and vibration, can beminimized. The load path is analogous to the current path in anelectrical circuit. Optimum force and moment sensing can be achievedwhen all the forces and moments originating from the tool tips aretransmitted through the sensor only and back to the supporting structureat the other end of the sensor, or the “ground”, therefore ensuring alltool-tips loads are gathered by the sensor before sending back the forceand moment signals back to the controller for interpretation.

FIG. 26 e shows a cross-section through the load path of theend-effector 428. The grounded portion consists of the base block 605that supports the backend of the force-moment sensor 608 only. All ofthe actuators 600 and 601, the tool-actuation sensor 604, and theircorresponding supporting structure are mounted to the front face of thesensor 608 free end. This excess weight read by the sensor 608 can beoffset by zeroing out the signal at the controller with the knownweights and center-of-gravity distances of each part contributing to theweight measured by the sensor 608, including those of the tool 430. Thisactive gravity compensation technique can be completed by computing theexpected dead weight of all parts at the sensor location with thedynamic equations of the manipulator, minus which the filtered signalfrom the sensor is the pure external forces and moments acting at thetool tips.

Besides tool-tips forces and moments, haptic feedback also includes thetool-actuation force feedback. Referring to FIG. 26 d, the closing andopening of the blades 506 and 508 of the tool 430 is achieved by thevertical motion of the piston 504. The piston 504 is carried by theactuator subassembly 452, which is connected back to the tool-actuationmotor 601 via the actuation bar 603. The pinch force at the tool tips ofthe blades 506 and 508, therefore, is transmitted vertically through theabove mentioned path. Thus a strain-gauge type sensor 604 is located atmiddle of the cantilever section of the actuation bar 603 to measure theelastic deformation of the bar 603 to provide tool-actuation forcefeedback to the controller. The voltage signal generated can be used inforce regulation for tool-actuation, or can be reproduced at thehand-controller for tool-actuation haptic feedback via an appropriatehuman-machine interface.

Referring to FIG. 16 a, surgical manipulator 400 is designed to be usedfor surgical operations in a telerobotic system under the direct controlof a surgeon 960. In a telerobotic system, a robot and a hand-controllerform a master-slave relationship as the operator moves thehand-controller, or the master, to perform the action, and the robot, orthe slave, carries out the actual operation as the output by followingthe hand motions of the operator. Referring to FIG. 30, the teleroboticsystem is comprised of two portions, the slave which is a mobileplatform 906 containing two manipulators 900 and 901, and the master inthe form of a workstation 908 including one or more computer monitor,and two haptic devices 903, 904 as hand-controllers, with eachmanipulator-hand-controller pair mimicking the left and right arm of asurgeon 960 such that dual-hand operation is possible.

The two manipulators 900 and 901 have mirrored configurations to eachother, with all components being identical. Thus the surgicalmanipulator system includes at least two surgical manipulators 900 and901 configured to be structural mirror images of each other, with one ofthe surgical manipulator being configured for left handed operation andthe other being configured for right handed operation. Thisconfiguration is advantageous in that it allows the surgical toolsattached to respective end-effectors to be brought into closestproximity with each other in a surgical site on a patient.

There is a communication system coupling the left and right handcontrollers to their respective surgical manipulators for translatingmovement of the left and right hand controllers to scaled movement ofthe first and second surgical manipulators. This scaled motion may bepredetermined in software and may be 1:1 in which the move of thesurgeons hand on the controller is translated into exactly the samemovement of the end-effector. However the ratio need not be 1:1depending on the surgical procedure involved.

For each of the manipulators 900 and 901, there is a tool tray 911located near the base of each manipulator. The tool tray 911 holds anumber of surgical tools which may or may not be identical to the toolsshown in FIGS. 22 a to 25 b, but are required for the planned surgicalprocedures. The manipulators 900 and 901 are programmed to change toolsautomatically at the tool tray 911 upon a single command from thesurgeon 960. Both manipulators 900 and 901 are mounted on the mobileplatform 906 which can easily be transported to dock with the operatingtable 907 and undock and remove when the operation is completed. Amicroscope and/or stereo camera 909, which can be mounted either on themobile platform 906 or as a fixture in the operating room, providesvisual display of the surgical site and/or the overview of themanipulators plus their tools with respect to the patient 962.

A single cable connection using regular network protocol may be used forcommunication of signals between the manipulators mobile platform 906and the workstation 908 at which the surgeon 960 is at. The lefthand-controller 903 by default controls the left manipulator 900, andthe right hand-controller controls the right manipulator 901, althoughthrough software selection the surgeon 960 can switch over thecommunication linkage between the pair if it is required during theoperation.

Each of the haptic devices 903 and 904 is a 6 DOF hand-controller thatcan measure a surgeon's hand motion in all six directions of translationand rotation in 3D space. The motion signals are then sent to theintended manipulator through the motion controller, at which thesurgeon's input will be reproduced. These signals can also be scaled,such that the surgeon 960 can fully utilize the best resolution of themanipulators motion by having their hand motions at the hand-controllers903 and 904 scaled down before being carried out by the manipulators. Atthe hand-controllers 903 and 904, switches are available for the surgeon960 to control other functions of the manipulators, such astool-actuation, dead-man switch, and automatic tool changing.

The hand-controllers 903 and 904 also have three to six powered jointsto provide haptic feedback to the surgeon 960. The base positions of thehand-controllers 903 and 904 on the workstation 908 can be adjusted tothe comfort of the surgeon 960, and with the addition of arm rests theonly motion required from the surgeon 960 is at the wrists. Since thereis no absolute referencing of the hand-controller motion with respect tothat of the manipulators, the surgeon 960 can hold the handles of thehand-controllers 903 and 904 at a comfortable posture, again to minimizefatigue, while the manipulators 900 and 901 are holding the surgicaltools in the appropriate positions. Also on the workstation 908, thereis one or more computer monitor 905 displaying system status and alsoproviding touch-screen interface to the surgeon 960 and/or nurses foradjusting critical system parameters.

One of the most important settings the surgeon 960 needs to make is thevirtual boundaries for the manipulators. Using a preoperative image withregistration back to the manipulator, or with a real-time intraoperativeimage taken by the camera 909, the surgeon 960 can specify on-screen theregion at the surgical site where the manipulator with the surgical tool430 can operate within. If the surgeon 960 commanded the manipulator viathe hand-controllers to move near these boundaries, the motioncontroller will automatically stop the manipulators from moving anyfurther unless the surgeon 960 reverse the motion. This will set aprohibited area where the manipulators cannot move the surgical toolsto, such that the surgeon 960 can ensure critical areas in the patient'sanatomy is protected. The monitor 905 also displays the real-time videotaken by the microscope and/or camera 909.

Alternatively, the microscope/camera 909 video signal can be displayedvia a digital eyepiece 910 which mimics that of a conventionalmicroscope if the surgeon 960 prefers. The surgeon 960 together with theworkstation 908 can be immediately next to the operating table 907 fortelepresence operation, where the surgeon 960 will directly observe thesurgical site on the patient 962 without any visual aid. In the case ofremote operation, the surgeon 960 and the workstation 908 is at aphysical distance from the operating table 907 limited only by thenetwork connection infrastructure available. Visual feedback via themonitor 905 and haptic feedback via the hand-controllers 903 and 904retain the senses of vision and touch of the surgeon 960 over thephysical distance, which makes remote teleoperation possible with theadditional benefits of finer and more consistent hand motion, moreergonomic user-interfaces to reduce surgeon 960 fatigue, less intrusiveto the surgical theatre, and built-in fail-safe features to protect thepatient 962 and the surgeon 960.

Besides teleoperation, the manipulators can also be operated usingpre-planned image-guided trajectories. Pre-operative images of thepatient's surgical site are taken with an external imager, such asfluoroscope or CT-scanner. The surgeon 960 can then use those images todefine where the problem exists, which area the manipulator needs to goto and with which surgical tool. The surgeon 960 can then take anintra-operative image with registration to the manipulator coordinatesystem, and map it to the pre-operative image with the planned targets.The control software will then interpret the targets into workspacecoordinates of the manipulators, thereby allowing the surgeon 960 tospecify the complete trajectories of the surgical tool held by themanipulator with respect to the surgical site of the patient 962. Uponexecution of the pre-planned trajectories, the surgeon 960 can eitherstart the autonomous motion of the manipulator and pause or rewind atany time at the workstation monitor, or use the hand-controller tocontrol the motion along the prescribed trajectories.

Comparing to the other devices available in the current market, thesurgical manipulator described herein has several advantages in thefield of microsurgeries, including brain, spine and eye surgery. Firstof all, this surgical manipulator is smaller than a regular human armthanks to the right-angle transmission modules and the compactness ofthe other actuation components, which allows easy access to the surgicalsite and minimizes intrusion to the operating room. Although beingcompact in size, this manipulator has broad enough motion range andreach to accomplish tasks requiring bigger manipulator workspace such assuturing. The 6 DOF available means dexterous motion is capable in anygiven direction. With high-power brushless servo motors deployed at eachjoint, relatively heavier-duty tasks such as tissue-retraction andbone-drilling for pedicle screw is made possible. The smallest step sizeachievable at the tool tip, due to the use of the right-angletransmission modules as well as high resolution sensors, amplifiers andmotion controllers, matches the finger motion resolution of the bestbrain surgeons. The auto tool-changing capability as a result of theend-effector design reduces the tool-changing time and also human-error.The end-effector structure forces the load-path to go through theforce-moment, and the consequent high fidelity of haptic feedbackretains the sense of touch of the surgeon, without which the surgeonwould lose a significant amount of surgical techniques and know-how.

As used herein, the terms “comprises”, “comprising”, “including” and“includes” are to be construed as being inclusive and open ended, andnot exclusive. Specifically, when used in this specification includingclaims, the terms “comprises”, “comprising”, “including” and “includes”and variations thereof mean the specified features, steps or componentsare included. These terms are not to be interpreted to exclude thepresence of other features, steps or components.

The foregoing description of the preferred embodiments of the inventionhas been presented to illustrate the principles of the invention and notto limit the invention to the particular embodiment illustrated. It isintended that the scope of the invention be defined by all of theembodiments encompassed within the following claims and theirequivalents.

1. A surgical manipulator, comprising: a) a base and a first right-angledrive mechanism mounted on said base, a shoulder-roll drive mechanismlocated in said base for rotating said first right-angle drive mechanismabout a shoulder-roll axis, said first right-angle drive mechanismincluding a first input pulley and a first output pulley mountedsubstantially perpendicular to said input pulley; said first right-angledrive mechanism including a bi-directional coupling mechanism forcoupling said first input pulley and said first output pulley, a firstdrive mechanism for rotating said first input pulley about a first inputaxis wherein rotation of said first input pulley is translated intorotation of said first output pulley by said bi-directional couplingmechanism about a shoulder-pitch axis which is substantiallyperpendicular to said first input axis; b) a lower robotic arm beingmounted at one end thereof to said first output pulley so that when saidfirst output pulley is rotated, said lower arm rotates about saidshoulder-pitch axis; c) a second right-angle drive mechanism mounted insaid lower robotic arm, said second right-angle drive mechanismincluding a second input pulley and a second output pulley mountedsubstantially perpendicular to said second input pulley, said secondright-angle drive mechanism including said first drive mechanism andsaid bi-directional coupling mechanism for coupling said second inputpulley and said second output pulley, wherein rotation of said secondinput pulley about a second input axis is translated into rotation ofsaid second output pulley by said bi-directional coupling mechanismabout an elbow-pitch axis substantially perpendicular to said secondinput axis; d) a robotic fore arm mounted on said second output pulleyof said second right-angle drive mechanism so that when said secondoutput pulley is rotated, said robotic fore arm rotates about saidelbow-pitch axis; e) a third right-angle drive mechanism mounted in saidrobotic fore arm, said third right-angle drive mechanism including athird input pulley and a third output pulley mounted substantiallyperpendicular to said second input pulley, said third right-angle drivemechanism including said first drive mechanism and said bi-directionalcoupling mechanism for coupling said third input pulley and said thirdoutput pulley, wherein rotation of said third input pulley about a thirdinput axis is translated into rotation of said third output pulley bysaid bi-directional coupling mechanism about a wrist-pitch axissubstantially perpendicular to said third input axis; f) a robotic wristmounted on said third output pulley of said third right-angle drivemechanism so that when said third output pulley is rotated, said roboticwrist rotates about said wrist-pitch axis; said robotic wrist includingan actuation mechanism coupled to a wrist output shaft for rotating saidrobotic wrist output shaft about a wrist-roll axis; and g) anend-effector mounted to said wrist output shaft, said end-effectorincluding gripping means for releasibly gripping a surgical tool whereinwhen said actuation mechanism is engaged said end-effector is rotatedabout said wrist-roll axis.
 2. The surgical manipulator according toclaim 1 wherein said first drive mechanism includes a spur-gearmechanism mounted in said base and including a pinion anti-backlash gearmeshed with a driven gear, a motor for rotating said pinion gear whichin turn rotates said driven gear and therefore the first right angledrive mechanism about a shoulder-roll axis, and including a motor brake.3. The surgical manipulator according to claim 2 wherein said motorincludes a servo motor integrated with a harmonic gear and an angularencoder for measuring rotational displacement of a motor shaft coupledto said pinion gear.
 4. The surgical manipulator according to claim 1wherein said end-effector includes a main body portion including aframe, a tool-yaw motor mounted on said frame, a tool-actuation motormounted on said frame, a tool holder mounted on said frame and beingdetachable therefrom, said tool holder being configured to hold saidsurgical tool, a tool-actuation mechanism mounted on said frame andbeing detachable therefrom, said tool-actuation mechanism beingconfigured to engage a piston on said surgical tool, said tool-actuationmechanism being coupled to said tool-actuation motor, and a tool-yawdrive mechanism mounted on said frame and being detachable therefrom,said tool-yaw drive mechanism being coupled to said tool-yaw motor,wherein upon activation of said tool-yaw drive mechanism said surgicaltool rotates about said tool-yaw axis and wherein upon activation ofsaid tool-actuation mechanism said piston is linearly retracted orlinearly extended with respect to said end-effector thereby activating atool portion of said surgical tool.
 5. The surgical manipulatoraccording to claim 4 wherein said end-effector includes a base blockwhich interfaces to the wrist, and wherein said end-effector includes atool-tip force-moment sensor which is a single mechanical linkagebetween said motor-support bracket and said base block.
 6. The surgicalmanipulator according to claim 4 wherein said tool-actuation motor is alinear actuator having an output shaft which moves up and down along amajor axis of the motor and at a distal end portion of said output shaftan actuator bar is connected at a first end portion thereof, saidactuator bar having a second end portion supported by a vertical guiderod and including an interface which couples to said tool-actuationmechanism, wherein said actuator bar transmits vertical motion of theoutput shaft to the tool-actuation mechanism which is mounted at thesecond end of the bar such that said vertical motion provides atool-actuation axis of motion for the end-effector.
 7. The surgicalmanipulator according to claim 6 wherein said end-effector includes atool-actuation force sensor mounted on said actuation bar between apoint where said actuation bar is supported by the vertical guide rodand the interface with the tool-actuation mechanism.
 8. The surgicalmanipulator according to claim 7 wherein said tool-actuation forcesensor is a strain gauge, at which point on the bar on which said forcesensor is mounted any elastic vertical deflection due to actuation ofthe surgical tool can be measured.
 9. The surgical manipulator accordingto claim 4 wherein said tool-yaw mechanism includes a frame, on which ismounted a pair of idler pulleys, a middle idler pulley and a drivepulley, including a toothed belt being routed on said idler pulleys,said middle idler pulley and said drive pulley, said toothed belt beingconfigured to engage a toothed pulley on said surgical tool, on twoopposite ends of a diameter of said toothed pulley, and whereinbi-directional rotation of the toothed belt driven by the drive pulley,converts tangential forces to rotary motion of said surgical tool. 10.The surgical manipulator according to claim 9 wherein said frame has anopen front-framed architecture and a toothed belt routing configurationon said idler pulleys and said middle idler pulley configured to allowthe surgical tool to be ejected/replaced from the open front of theend-effector.
 11. The surgical manipulator according to claim 9 whereinsaid frame includes sheet metal flexures supporting said outer idlerpulleys so that said outer idler pulleys can be passively spread outenough to completely disengage the surgical tool thereby eliminating anyfrictional effects, and wherein when engaged with said surgical tool,the metal flexures allow a constant preload to the toothed belt duringtool yawing but can also manually collapse, when no surgical tool ispresent, for facilitating toothed belt replacement.
 12. The surgicalmanipulator according to claim 9 wherein said tool-yaw motor mounted onsaid frame includes a drive shaft having a shape complementary to ashape of a bore on the drive pulley for insertion into the bore forenabling torque to be transmitted to the tool-yaw mechanism, whileallowing easy de-coupling of the shaft from the drive pulley.
 13. Thesurgical manipulator according to claim 9 wherein said tool-yaw motorincludes a servo motor integrated with an anti-backlash spur gearheadand an incremental encoder.
 14. The surgical manipulator according toclaim 4 wherein said magnetic tool holder, said tool actuator, and saidtool-yaw mechanism are sterile subassemblies, with quick release andattachment features for quickly attaching and detaching them to and fromsaid main body portion.
 15. The surgical manipulator according to claim4 wherein said main assembly including said tool-yaw motor, saidtool-actuation motor, said tool-tip force-moment sensor and saidtool-actuation force sensor are encapsulated in a protective drape bagwhich covers from the base of the surgical manipulator all the waythrough the entire length of the robotic fore arm, lower arm and roboticwrist and up to a front face of the end-effector main assembly.
 16. Thesurgical manipulator according to claim 2 wherein said tool holderincludes a support body having an elongate channel having a sizesuitable to receive therein the cylindrical tool body of surgical tool,and wherein said cylindrical tool body is made of a magnetic material,and wherein said support body includes at least one magnet embeddedtherein adjacent to said groove for magnetically restraining saidmagnetic cylindrical tool body.
 17. The surgical manipulator accordingto claim 16 wherein said support body is made of a material which allowsthe surgical tool to rotate with minimal friction within support bodywhen rotated by said tool-yaw mechanism.
 18. The surgical manipulatoraccording to claim 16 wherein said surgical tool includes flanges on thebody of the surgical tool for locating and constraining the surgicaltool axially within said channel in support body due to a close axialfit with the support body.
 19. The surgical manipulator according toclaim 16 wherein said tool holder includes a tool release mechanismincluding a pair of tool-ejection wings pivotally mounted on supportbody with a portion of each wing located in said channel behind saidtool body and configured such that once said tool-ejection wingscompressed on outer surfaces thereof, tool-ejection wings pivot in ascissor action, to strip the tool body away from said at least onemagnet responsively ejecting said tool from said tool holder.
 20. Thesurgical manipulator according to claim 19 wherein said tool-actuationmechanism includes a pair of pivoting fingers pivotally mounted to asupport member with matched end portions configured to engage and holdtherebetween a portion of a piston on the surgical tool.
 21. Thesurgical manipulator according to claim 20 including a tool changermechanism comprising a tool storage and tool change tray, said toolchange tray including a support structure for holding the surgical toolsand including engaging features arrayed on said tool change trayconfigured to simultaneously spread said pulleys apart, engage thepivoting fingers located on said tool-actuation mechanism, and engagesaid ejection-wings located on said tool holder thereby releasing saidsurgical tool from said end-effector.
 22. The surgical manipulatoraccording to claim 21 wherein said support structure for holding thesurgical tools and said engaging features arrayed on said tool changetray include first and second pair of pins fixed in vertical arrangementto said tool tray being positioned and spaced apart such that theyengage said pulleys on said tool-yaw mechanism and spread said pulleysapart when said end-effector engages said passive tool changer whenpicking up a surgical tool or releasing a surgical tool, and including athird pair of pins positioned on said tool change tray with respect tosaid first and second pairs of pins such that the third pair of pinsengage pivoting fingers located on said tool-actuation mechanismresponsively pivoting said fingers out of engagement with said piston onsaid surgical tool, said tool change tray including mating ejectionlatches mounted on the tool tray which line up with said ejection-wingslocated on said tool holder, which mating ejection latches include aspring-loaded pliers-like mechanism to provide a cushionedtool-ejection.
 23. The surgical manipulator according to claim 21wherein each surgical tool includes identifying means mounted thereon,and wherein said tool changer includes a tool-identification sensor forsaid identifying means.
 24. The surgical manipulator according to claim23 wherein said identifying means includes a radio frequency (rf) tagand, and wherein said reading means includes an rf receiver.
 25. Thesurgical manipulator according to claim 23 wherein said identifyingmeans includes a bar code, and wherein said reading means includes a barcode reader.
 26. The surgical manipulator according to claim 1 whereinsaid surgical manipulator is a first surgical manipulator, including atleast a second surgical manipulators and configured to be structuralmirror images of each other, said first surgical manipulator beingconfigured for left handed operation and said at least a second surgicalmanipulator being configured for right handed operation to allow thesurgical tools attached to respective end-effectors to be brought intoclosest proximity with each other in a surgical site on a patient. 27.The surgical manipulator according to claim 1 wherein said first, secondand third right-angle drive mechanisms each include a) a housing andwherein said first drive mechanism includes a harmonic drive mounted onsaid housing being connected to said input pulley for rotation aboutsaid first rotational axis; b) the output drive shaft having a secondaxis of rotation, said output shaft being connected to said outputpulley, said output pulley being mounted in said housing for rotationabout said second rotational axis, said input and output pulleys beingmounted in said housing and positioned with respect to each other suchthat a pre-selected angle is established between said first and secondaxes of rotation; c) said bi-directional coupling mechanism for couplingsaid first input pulley and said first output pulley comprising a cabledrive mounted in said housing, said cable drive including, at least oneflexible cable, said input and output pulleys each including at leastone cable guide for receiving therein said at least one flexible cable,idler means for guiding said at least one flexible cable between saidinput and output pulleys, wherein when the input pulley rotates in onedirection about said first axis of rotation, said at least one flexiblecable pulls the output pulley and output shaft to rotate in onedirection about said second rotational axis, and when the input pulleyrotates in the other direction about said first axis of rotation, saidat least one flexible cable pulls the output pulley and output shaft torotate in an opposite direction about said second rotational axis.
 28. Asurgical manipulator system, comprising: a) at least first and secondsurgical manipulators according to claim 26; b) left and right handcontrollers with the right hand controller being associated with thefirst surgical manipulator and the left hand controller being associatedwith the second surgical manipulator, said at least first and secondhand controllers being configured to be operated by a surgeon; and c)communication system coupling said left and right hand controllers tosaid at least first and second surgical manipulators for translatingmovement of said left and right hand controllers to scaled movement ofsaid at least first and second surgical manipulators.
 29. The surgicalsystem according to claim 28 including a vision system focused on a workarea including an area of a patient to be operated on and focused on theend-effectors and associated surgical tools attached to said at leasttwo surgical manipulators, said vision system including display meansfor displaying images of said work area to a surgeon.
 30. The surgicalsystem according to claim 29 including a vision system focused on a workarea including an area of a patient to be operated on and focused on theend-effectors and associated surgical tools attached to said at leasttwo surgical manipulators, said vision system including display meansfor displaying images of said work area to a surgeon.
 31. The surgicalsystem according to claim 29 configured for teleoperation wherein saidsurgeon is located remotely from said patient.
 32. The surgical systemaccording to claim 28 wherein said end-effector includes a tool-tipforce-moment sensor mounted to said end-effector and configured to sensetool tip force and moment at a tip of the surgical tool, and whereinsaid end-effector includes a tool-actuation force sensor mounted thereonconfigured to measure actuation forces on a tip of the surgical tool,and wherein said communication system coupling said left and right handcontrollers to said at least first and second surgical manipulators isconfigured to communicate said forces and moments to said left and righthanded controllers providing haptic feedback to said surgeon.
 33. Thesurgical manipulator according to claim 32 wherein said tool-actuationforce sensor is a strain gauge.
 34. A drive device for transmittingrotational motion about one axis to rotational motion about anotheraxis, comprising: a) a housing and a harmonic drive mounted on saidhousing being connected to an input pulley for rotation about a firstrotational axis; b) an output drive shaft having a second axis ofrotation, said output shaft being connected to an output pulley, saidoutput pulley being mounted in said housing for rotation about saidsecond rotational axis, said input and output pulleys being mounted insaid housing and positioned with respect to each other such that apre-selected angle is established between said first and second axes ofrotation; c) bi-directional coupling mechanism for coupling said firstinput pulley and said first output pulley, comprising a cable drivemounted in said housing, said cable drive including, at least oneflexible cable, said input and output pulleys each including at leastone cable guide for receiving therein said at least one flexible cable,idler means for guiding said at least one flexible cable between saidinput and output pulleys, wherein when the input pulley rotates in onedirection about said first axis of rotation, said at least one flexiblecable pulls the output pulley and output shaft to rotate in onedirection about said second rotational axis, and when the input pulleyrotates in the other direction about said first axis of rotation, saidat least one flexible cable pulls the output pulley and output shaft torotate in an opposite direction about said second rotational axis. 35.The drive device according to claim 34 wherein said at least oneflexible cable is a pair of flexible cables, said input pulley includinga first circular section having a first diameter and a second circularsection having at least a second diameter rigidly attached to said firstcircular section, said at least a second diameter being smaller thansaid first diameter, a circumference of the first and said at least asecond circular sections each having a groove with the groove in thecircumference of the first section for receiving therein a firstflexible cable of said pair of flexible cables and the groove in thecircumference of the at least a second section for receiving therein asecond flexible cable of said pair of flexible cables, said idler meansincluding a pair of idlers each having an idler shaft and a first and atleast a second idler pulley mounted in said housing and aligned along anaxis perpendicular to said first and second rotational axis with saidfirst idler pulley configured for guiding said first flexible cablebetween said grooves on the first sections of said input and outputpulleys, and said at least a second idler pulley configured for guidingsaid at least a second flexible cable between said grooves on said atleast a second sections on said input and output pulleys.
 36. The drivedevice according to claim 35 wherein said cable drive includes a cabletension adjustment mechanism for adjusting a tension of said at leastone flexible cable.
 37. The drive device according to claim 36 whereinsaid cable tension adjustment mechanism is manually operable toeliminate any slack in said at least one cable.
 38. The drive deviceaccording to claim 36 wherein said cable tension adjustment mechanismincludes an autotensioning spring mechanism configured apply tension tosaid at least one cable to eliminate any slack in said at least onecable.
 39. The drive device according to claim 36 wherein said cabletension adjustment mechanism includes an autotensioning rachetingmechanism configured to rachet said at least one cable to eliminate anyslack in said at least one cable and lock said autotensioning rachetingmechanism.
 40. The drive device according to claim 34 wherein said atleast one cable is four cables, and wherein said cable drive includescable tension adjustment means for adjusting a tension of said at leastone flexible cable, said cable tension adjustment means including atleast four tensioning screws connected to said output pulley, said atleast four cables each having two ends and being connected at one endthereof to said tensioning screw and connected at the other end thereofto a termination at said input pulley, wherein a tension in said eachcable is adjusted by turning the corresponding said tensioning screw.41. The drive device according to claim 34 wherein said harmonic driveconnected to said input pulley is configured to provide a substantiallybacklash free output.
 42. The drive device according to claim 34 whereinsaid input and output pulleys are mounted in said housing in saidpre-selected position such that said pre-selected angle establishedbetween said first and second axes of rotation is 90 degrees so thatsaid second axis is perpendicular to said first axis.
 43. The drivedevice according to claim 34 including a positioning mechanism mountedin said housing for adjusting the position of said output pulley withrespect to said input pulley so that said pre-selected angle establishedbetween said first and second axes of rotation is adjustable.
 44. Thedrive device according to claim 34 wherein said at least one flexiblecable is a low-stretch/pre-tensioned cable to minimize transmission lossdue to elastic stretching of the cable.
 45. The drive device accordingto claim 34 including a sensor engaged with said output shaft formeasuring rotational displacement or speed or both of said output shaft.46. The drive device according to claim 34 including a brake configuredto engage with said output shaft to provide mechanical braking action tothe output shaft.
 47. A surgical end-effector, comprising: a main bodyportion including a frame having an interface configured to be attachedto a robotic arm, a tool-yaw motor mounted on said frame, atool-actuation motor mounted on said frame; a tool holder mounted onsaid frame and being detachable therefrom, said tool holder beingconfigured to hold a surgical tool; a tool-actuation mechanism mountedon said frame and being detachable therefrom, said tool-actuationmechanism being configured to engage a piston on said surgical tool,said tool-actuation mechanism being coupled to said tool-actuationmotor; and and a tool-yaw drive mechanism mounted on said frame andbeing detachable therefrom, said tool-yaw drive mechanism being coupledto said tool-yaw motor, wherein upon activation of said tool-yaw drivemechanism said surgical tool rotates about said tool-yaw axis andwherein upon activation of said tool-actuation mechanism said piston islinearly retracted or linearly extended with respect to saidend-effector thereby activating a tool portion of said surgical tool.48. The surgical end-effector according to claim 47 wherein saidinterface includes a base block which interfaces to a wrist of a roboticarm, and wherein said end-effector includes a tool-tip force-momentsensor which is a single mechanical linkage between said motor-supportbracket and said base block.
 49. The surgical end-effector according toclaim 47 wherein said tool-actuation motor is a linear actuator havingan output shaft which moves up and down along a major axis of the motorand at a distal end portion of said output shaft an actuator bar isconnected at a first end portion thereof, said actuator bar having asecond end portion supported by a vertical guide rod and including aninterface which couples to said tool-actuation mechanism, wherein saidactuator bar transmits vertical motion of the output shaft to thetool-actuation mechanism which is mounted at the second end of the barsuch that said vertical motion provides a tool-actuation axis of motionfor the end-effector.
 50. The surgical end-effector according to claim49 including a tool-actuation force sensor mounted on said actuation barbetween a point where said actuation bar is supported by the verticalguide rod and the interface with the tool-actuation mechanism.
 51. Thesurgical end-effector according to claim 50 wherein said tool-actuationforce sensor is a strain gauge, at which point on the bar on which saidforce sensor is mounted any elastic vertical deflection due to actuationof the surgical tool can be measured.
 52. The surgical end-effectoraccording to claim 47 wherein said tool-yaw mechanism includes a frame,on which is mounted a pair of idler pulleys, a middle idler pulley and adrive pulley, including a toothed belt being routed on said idlerpulleys, said middle idler pulley and said drive pulley, said toothedbelt being configured to engage a toothed pulley on said surgical tool,on two opposite ends of a diameter of said toothed pulley, and whereinbi-directional rotation of the toothed belt driven by the drive pulleyconverts tangential forces to rotary motion of said surgical tool. 53.The surgical end-effector according to claim 52 wherein said frame hasan open front-framed architecture and a toothed belt routingconfiguration on said idler pulleys and said middle idler pulleyconfigured to allow the surgical tool to be ejected/replaced from theopen front of the end-effector.
 54. The surgical end-effector accordingto claim 52 wherein said frame includes sheet metal flexures supportingsaid outer idler pulleys so that said outer idler pulleys can bepassively spread out enough to completely disengage the surgical toolthereby eliminating any frictional effects, and wherein when engagedwith said surgical tool, the metal flexures allow a constant preload tothe toothed belt during tool yawing but can also manually collapse, whenno surgical tool is present, for facilitating toothed belt replacement.55. The surgical end-effector according to claim 52 wherein saidtool-yaw motor mounted on said frame includes a drive shaft having ashape complementary to a shape of a bore on the drive pulley forinsertion into the bore for enabling torque to be transmitted to thetool-yaw mechanism, while allowing easy de-coupling of the shaft fromthe drive pulley.
 56. The surgical end-effector according to claim 52wherein said tool-yaw motor includes a servo motor integrated with ananti-backlash spur gearhead and an incremental encoder.
 57. The surgicalend-effector according to claim 47 wherein said magnetic tool holder,said tool actuator, and said tool-yaw mechanism are sterilesubassemblies, with quick release and attachment features for quicklyattaching and detaching them to and from said main body portion.
 58. Thesurgical end-effector according to claim 47 wherein said main assemblyincluding said tool-yaw motor, said tool-actuation motor, said tool-tipforce-moment sensor and said tool-actuation force sensor areencapsulated in a protective drape bag which covers from the base of thesurgical manipulator all the way through the entire length of therobotic fore arm, lower arm and robotic wrist and up to a front face ofthe end-effector main assembly.
 59. The surgical end-effector accordingto claim 47 wherein said tool holder includes a support body having anelongate channel having a size suitable to receive therein thecylindrical tool body of surgical tool, and wherein said cylindricaltool body is made of a magnetic material, and wherein said support bodyincludes at least one magnet embedded therein adjacent to said groovefor magnetically restraining said magnetic cylindrical tool body. 60.The surgical end-effector according to claim 59 wherein said supportbody is made of a material which allows the surgical tool tool to rotatewith minimal friction within support body when rotated by said tool-yawmechanism.
 61. The surgical end-effector according to claim 59 whereinsaid surgical tool includes flanges on the body of the surgical tool forlocating and constraining the surgical tool axially within said channelin support body due to a close axial fit with the support body.
 62. Thesurgical end-effector according to claim 59 wherein said tool holderincludes a tool release mechanism including a pair of tool-ejectionwings pivotally mounted on support body with a portion of each winglocated in said channel behind said tool body and configured such thatonce said tool-ejection wings compressed on outer surfaces thereof,tool-ejection wings pivot in a scissor action, to strip the tool bodyaway from said at least one magnet responsively ejecting said tool fromsaid tool holder.
 63. The surgical end-effector according to claim 62wherein said tool-actuation mechanism includes a pair of pivotingfingers pivotally mounted to a support member with matched end portionsconfigured to engage and hold therebetween a portion of a piston on thesurgical tool.